The British rocker was recording a radio gig for BBC Radio 2 when he discovered the hip-hop star was in the next studio recording the soundtrack for MISSION: IMPOSSIBLE 3.
A studio source says, "Kanye didn't mind being interrupted and after Coldplay's show, Chris joined him in the recording booth for a jamming session.
"They did a track together which sounded amazing. Fingers crossed it will see the light of day."
Both Coldplay and West will be performing at the Brit Awards at the British capital's Earls Court venue tonight (15FEB06).