Ms Cherie Blair said yesterday she was thoroughly looking forward to enjoying the pregnancy which took her and her husband by surprise.
The Prime Minister's wife spoke about her feelings for the first time since the news that she was expecting her fourth child broke last week, and confirmed that she was feeling on top form.
Appearing as guest of honour at the first performance to be staged in London's newly refurbished Royal Opera House, Ms Blair said: "Every baby is a miracle, and this one was certainly a surprise.
"I am looking forward to going through this pregnancy very much."
Ms Blair, who is now 13 weeks pregnant, received rapturous applause from the 350-strong audience, mainly of children from London.
She appeared on stage alongside Sir Anthony Dowell, director of the Royal Ballet, to introduce an hour-long performance by the Royal Ballet and the Royal Ballet School.
Standing on the stage, she told her audience that she thought her time caring for babies had passed and she remembered those times with nostalgia.