When the singer Art Garfunkel found himself in Mexico working on Mike Nichols's film version of Joseph Heller's hilarious anti-war satire Catch-22, he was not so much excited as worried. "There I was with real actors like Alan Arkin and Orson Welles wondering what I was doing; it was a little bit strange." Apprentice actor he was, but at that time he was already famous as the man with the voice range to sing Bridge Over Troubled Water.

It was Garfunkel's first movie and it had not been his idea. Acting had not been an ambition. "We [Simon and Garfunkel] had done the soundtrack for The Graduate and that gave Mike Nichols the idea of casting me as Nately the innocent. Mike arrived at the brownstone [house] I was living in in New York and offered me the part." Shooting began on January 2nd, 1969.

"I was scared, very insecure," he says in that slow, emphatic drawl. "I had no acting style. I just tried to make it seem easy. At that stage I had not read the novel. But then I did and the script as well. It was a tricky book to do - the only way to make it was a series of set pieces."

So there they all were, on a beach in Mexico in 1969 at the height of the Vietnam War. Heller's book is the definitive war novel, so was the movie intended as an anti-war gesture? "I'm always wary about making statements about the evils of war, the rights and wrongs, whether a war is necessary or not. I don't believe in the black and white or anything. Do you? Life is all about shades of grey. And if you look at war from an American's point of view, it's always tricky - we've never known what it's like to be invaded." Garfunkel does not like easy answers. As for what the war meant to him, he says: "Well, I was very interested in avoiding it. I was committed to saving my neck."

He is polite, formal, unhurried and soon gives the impression that should you be suspended by one hand from the edge of a cliff, he would first exchange greetings before deciding what to do next. In contrast with Simon's intense, obsessive, song-writing genius, Garfunkel has always had a benign, gracious demeanour, the tall rangy boy with the beautiful voice and a penchant for white shirts and black waistcoats. Slightly goofy, although as he says himself: "Oh I'm pretty intense," - obviously he is just better at hiding it. "All my life I've been trying to give the impression of seeming easy going." Whereas Simon seemed preoccupied, Garfunkel invariably looked pleasantly surprised. The irony of his having appeared in Catch-22, that novel of no escape, is not lost on him either. His entire career is caught in its own Catch-22. No matter what he has achieved as performer - there have been good performances such as in Bad Timing, there have been strong solo songs, I Believe (When I fall in love it will be forever), Break- away, and Bright Eyes - it always comes back to Simon and Garfunkel.

The pair met up as schoolboys in the mid-1950s and first recorded under the name of Tom and Jerry, presumably inspired by the difference in their height - although Garfunkel makes some joke about the smart little guy and the victim. Later, as college students in 1963, they formed the folk-rock partnership which would create a phenomenal body of enduring classics: The Sound of Silence, Scarborough Fair, Homeward Bound, Mrs Robinson, America, Bridge Over Troubled Water, The Boxer, Only Living Boy in New York, Song for the Asking - brilliant harmony, intelligent lyrics and catchy, often haunting tunes. In 1977, Bridge Over Troubled Water received the Britannia Award for the best international pop album and single 1952-1977, as voted by the British music industry. It remains one of the biggest-selling records of all time.

"Please don't ask me are we getting back together," groans Art Garfunkel, not that I had intended to. There have been reunions, most noticeably The Concert in Central Park in September 1981 when 500,000 New Yorkers and others, of all ages, turned up, and a charity gig in 1992, but even an optimist would have to accept the inevitable at this stage. Both are approaching 60 and have long since settled into solo careers with Simon's excursions into African music producing such exciting results as the Graceland album in 1986.

Even so, some partnerships, at least in their public's opinion, are never allowed to break up. As much has been written about the relationship between this pair, who were inducted into the Rock and Roll Hall of Fame in 1990, as about their music.

"I have spent a long time trying to establish my own identity as an actor, a singer, a Renaissance man," says Garfunkel. Funny, touchy, unpredictable, he seems like the sort of character who would bring pillow slips on a camping trip. There is a fastidious quality to his intellectualising. Currently on a European tour which brings him to Dublin next week, he has humour enough to check into his hotel in Athens under the name of Gunter Gribling, but his offbeat wit, while unmistakably New York, is more strategic than aggressive.

Asked if he has a strong sense of history, he considers the question before conceding: "I'm not sure what that means but I am informed by the past. As with so many Americans, my family came from Europe." His grandparents on both sides came from eastern Romania, from Moldavia, where the Danube flows into the Black Sea, in the early years of the century. Their names are on the list at Ellis Island. In 1996 he gave a concert there.

"Both of the families came from Iasi, it's a small village." For him, it's as much Russia, bordered as it is by the Ukraine, as it is Romania. He has never been there but still hopes to make the trip.

"I did go to Russia when it was the old Soviet Union under Andropov. I went to Leningrad, Minsk, Smolensk, Kiev, Moscow, and was heading south, but God what a depressing place. I just went home; it was too grim to stay on."

Describing the settlement in New York of Jews like his family, he says: "The Lower East Side was where all the Jewish immigrants settled. Then they moved to Brooklyn and from Brooklyn to Queens where they joined the middle classes. My parents were living in Forest Hills when I was born. Mr Simon was born in Newark and his family moved to Forest Hills when he was two."

Garfunkel, who refers to his former singing partner as "Mr Simon" throughout the interview, was born on October 13th 1941, exactly a year to the day before Mr Simon. "I'm the middle son of three. I always think middle children have the best of both worlds; you're somebody's younger brother as well as somebody's older brother."

He says that as a child he was "greatly loved". "We all were. We were made to feel valued. Our parents always let us feel important and wanted. I think your entire life is decided by how you are treated in your first six years. It gives you the confidence to do things." Extending this thesis, Garfunkel speaks about the way America seems to make things possible. While he fiddles about with the question of what America means to him, he does stress the unique opportunities his country offers.

"I think that in America if you try hard at anything, if you try to do something well, the rewards are great. It is unlike anywhere else. I was given chances and I took them, I rehearsed a lot in my teenage years, and have done well. I'm a millionaire." It is the first time I have ever heard anyone admit to being so wealthy. There is no bravado. Garfunkel is not bragging. It is simply a statement of fact. But it is dramatic. Is he serious though? "Oh yeah," he says mildly, "I've done well."

His childhood marked the emergence of the Garfunkel family into the American middle class. His father was a travelling salesman. "He sold sportswear, not sports gear - jackets and things. Bomber jackets were really big. Leisure wear. He would pack up the car and go upstate, to Albany and so on and be gone for a few days at a time. And we'd miss him and then he'd be back." The young Garfunkel was bright and scored well enough in an IQ test to be able to skip a grade. "Not such a good idea. It meant I was always the youngest kid in the class. It's not an advantage. It was just thought I'd be an attorney or an architect."

Aside from his now developing interest in recording Yiddish words from his best source, his mother, was being Jewish important? "There are three types of Jew. There are the orthodox, who are very strict, and there are the liberal, who are keen on assimilating. And then there is the middle group like us, pretty relaxed about it. I have to say my Jewishness has always been a backdrop to my life. Life's difficult and I turn to my own resources rather than the Jewish religion when I'm trying to make sense of things. I'd look to any set of customs, ceremonies and traditions that helped," and says he is drawn to Buddhism.

It is not surprising as he is philosophical. "I remember having a terrible long argument with my father on the phone. I slammed it down and said to myself I'm not going to call back, what did I care? But then I thought about it. I saw my father as a philosopher with his own philosophy and me as one with mine. I called back and am so glad I did. It was the late 1980s and he died soon after that." Were they close? "Yes. We had a deep love for each other. He was the most sentimental, loving man." Is he sentimental? "Yes. I'm a great lover. Even as a singer. I caress the words."

His mother is still alive. "She's in her 80s and she's doing great. She looks like someone in her 50s." Defying time obviously runs in the family - Garfunkel's boyishness lasted a long time. It proved a useful quality when playing Sandy in Carnal Knowledge (again directed by Nichols), in which he starred opposite Jack Nicholson. It is the story of two men who sustain a friendship from their college days into disappointing middle age.

While Nicholson's performance as the competitive, discontented womaniser who has an affair with his best friend's first girlfriend and later wife, is characteristicaly over the top, Garfunkel's is impressively understated and convincing.

One drawback of interviewing by phone is not being able to see if time has finally caught up with Garfunkel. Has it? He laughs at the question and replies he still looks younger. "It's genetic. Even my eight-year-old son James looks younger than his age." Admittedly, the Art Garfunkel who appears in Jennifer Lynch's controversial film, Boxing Helena, looks middle aged, but he has had a longer youth than most and knows it.

As a child he took piano lessons for five years but admits to being suspicious of musical training. "I think it can have a bad effect; too much schooling can have a bad effect. You lose your ego. It can make a talent puny." The only track on which he plays an instrument (the keyboard) is Silent Night on the Parsley, Sage, Rosemary and Thyme album. He sang in choirs. "I sang to please, I sang in school choirs, I sang in the synagogue. My early childhood up to about 13 was intensely sporty. Basketball, softball, the usual." But then music began to take over. "It is kind of strange. You don't think of becoming a troubadour. I was from a very conservative background, not typical of the music scene."

By 11 he was singing the songs of the Everly Brothers. He had also met up with a neighbourhood kid, Paul Simon. In 1957 Tom and Jerry had a small hit with Hey Schoolgirl, their first single - co-written. Having cracked the mysteries of the recording business at such an early age, Garfunkel's naturally practical instincts asserted themselves and he went to college to study architecture. "I did three-and-a-half years of it before realising I would never practise and switched to arts and majored in maths and later did a masters. All in all I was eight years at Columbia."

In 1962 he met up again with Simon who by then had taken a degree in English and chalked up a few unhappy months as a law student. In hindsight, their place in music history is guaranteed. Simon's range as a songwriter has surpassed even that of the other great icon of their era, Bob Dylan. In that mid-1960s hippie period though, Simon and Garfunkel, the college boys, must have looked so normal and respectable and, well, so clean as to be considered odd.

Asked about that era and all the love culture he says: "It was very exciting. It was about conservative America beginning to relax. I was a product of Eisenhower's America. It was very conservative. There was a release about the 1960s. It was life-affirming. But," he adds, obviously referring to Vietnam, "it was a mixed picture".

If Carnal Knowledge left him feeling "so I can act", Nicholas Roeg's complex psychological thriller Bad Timing, released in 1980, was a challenge. By then he had emerged as a solo artist but was still very much a nice guy in the public's eye. In Roeg's film, which is set in Vienna, Garfunkel plays a young American psychoanalyst who becomes involved with another American played by Theresa Russell. The affair goes badly wrong.

"It was very intense." Of his fine performance, he says: "I ran that race with a tremendous intensity. The idea that love takes us to the moon was reversed as they [the lovers] go straight to hell. My character just wants to get away from her and that makes him ruthless in the face of her emotional blackmail." That movie and his performance in it are, as he says, "all purple and dark grey".

The late 1970s were tough. His first marriage ended after a couple of years, and his solo albums with their distinctive, gentle sound, though praised, had to compete against his work with Paul Simon. After the break with him, Garfunkel worked on a debut solo album. Angel Clare, with its soft romantic sound, and featuring Van Morrison's I Shall Sing and a couple of Jimmy Webb tunes, was released in 1973.

Breakaway followed in 1976 and Fate for Breakfast, which included Bright Eyes, came three years later. Within a month of Scissors Cut appearing in 1981, the duo were reunited for The Concert in Central Park, the live recording of which resulted in a million-selling album. Of the success of his own records he says: "I've never had the big hits by myself and I do think my solo albums are under-appreciated." Which has been most successful? "Breakaway" - the answer is short and sharp.

Taking a break from performing, he hiked across Japan in 1982 and enjoyed it. "I like to be by myself. It's an expression of freedom." It began a ritual. Two years later he took his first long walk across America, with the intention of eventually crossing the continent from east to Pacific west coast and did so in 40 or so stages by 1996.

"I suppose it makes me interesting," he says. "I think it's always good to be at least slightly eccentric." He mentions a book of prose poems: "It's called Still Water. I think it explains a lot about how I think."

He still lives in New York, now with his wife, singer Kathryn Cermak, and their eight-year-old son James. So he became a father for the first time at 50? This observation is instantly countered: "I was 49."

Between 1963 and 1970, Simon and Garfunkel made five albums and won five Grammy Awards. Why were Simon and Garfunkel so good? How come they have survived? "Well, the songs had melody, thoughtful lyrics; the writing was wonderful, the singing good and above all - and I think this is very important - they were very well made. We paid huge attention to production values at a time when most singers didn't." He praises producer/sound engineer Roy Halee who did "fantastic work on them and I think that attention to detail is also true of my solo albums".

Will Simon and Garfunkel songs feature in his Dublin concerts? "But of course," he says in a mock central European accent. Acting and solo singing aside, he must be very proud of the enduring Simon and Garfunkel achievement? "You bet," he replies. And it sounds as if he means it.

Art Garfunkel sings in the Olympia, Dublin next Tuesday and Wednesday