And when Bacharach did indeed come to London last week, the pair got in contact and Noel's appearance, three quarters way through the set, was arranged.
Noel started the evening in his seat in the audience, alongside brother Liam, Patsy Kensit and Oasis' Paul McGuigan. When the time came, Noel went onstage, sat on a stool beside the piano and sang his favourite Burt song,"This guy's in love with you", while Bacharach split his time between playing the piano and conducting the BBC Concert Orchestra. Noel later told an ITN reporter that he was more nervous singing there than in front of 150,000 people with Oasis.
A source close to the concert organisers said:"Noel's apperance was a hush-hush thing. Obviously there were rumours, but we did'nt know it was going to happen for sure right up until the soundcheck, when they had a rehearsal.
"They were keeping it quite quiet. Noel did'nt want it turned into a media circus, because it would have ruined Burt's concert.
"Noel went on stage as a fan, not to milk the audience, though he got a rapturous reception. There were teenagers, middle-aged people and others in their sixties, and they all really appreciated it. They went wild.
"It was'nt a rock and roll thing. Noel was very genial and quite respectful. When he came on, he looked like he had a few nerves, and he was quite excited about it too.
"At the end, Noel and Burt embraced, and lapped the applause up, and then Noel walked off.
"I thought it was magical, really. It was really, really impressive. And Burt though it was great."
Asked if there was any likelihood of the unlikely partnership continuing, the source said "I know there's been talk of them maybe writing a song together or something, and there could be quite a possibility now they've made more of an acquaintance and worked together once.
"Maybe something will happen. I'm sure Noel would be quite eager". Noel's spokesman said "Nothing is planned. We'll just have to wait and see". Asked about Liam's reaction to the performance, Noel's spokesman said:"Liam and patsy though it was astounding. They were up on their feet at the end, cheering. Liam was really proud.
"It seriously was stunning. Noel's voice was truly amazing. He was chuffed, completely".
After the concert, the Oasis party carried in at Browns to celebrate with other clubbers including Sandra Bullock, Val Kilmer and Steven Dorff.