U2 have unveiled their first song for at least three years as part of the trailer for the forthcoming Mandela biopic A Long Walk To Freedom.

An excerpt from the song indicates Ordinary Love is a mid-tempo piano-driven ballad. It features the lyrics: “We can’t fall any further and/We can’t feel ordinary love/ We can’t reach any higher/ We can’t deal with ordinary love.”

The song was specially written for the movie, so it is unclear whether or not it will appear on the new U2 album.

A Long Walk To Freedom producer Harvey Weinstein said the band were asked to contribute a song to the film. "It was the fastest 'yes' I have ever received. The band saw various cuts of the film over the summer and worked diligently to write a song that truly reflects Nelson Mandela. I think they did a brilliant job, honouring the man and the leader they have known for over 20 years," he said.

The film stars Idris Elba as Mandela and Naomie Harris as Winnie Mandela, and is based on the former South African president's bestselling autobiography about his time in Robben Island as a political prisoner.

The film had its world premiere earlier this year at the 2013 Toronto International Film Festival.

Ordinary Love will be unveiled in full on the U2.com website on October 30th, and also on YouTube.

The band are currently recording their follow-up to No Line On the Horizon, which was released to mixed reviews in 2009.

No release date has been set for the new record but it will not before Christmas.

A Long Walk to Freedom will go on general release on November 29th.