In her biography, Be My Baby
, Ronnie Spector talks about the instant attraction her and John Lennon had for one another.
Obviously, she was married to Phil at the time...but as I recall, John took her into a room and started kissing her and, well, I'm not sure what else happened. All I recall is that she found him amazing (as a person) and saw him several times, and then for a long time didn't see him until, I believe, 1980. She mentioned how he looked soooo
much thinner, but gorgeous.
Anyway, I couldn't find a snippet from her book but here is a 2009 interview where she mentions John:
Here is her version of "Happy Xmas" on the 30th anniversary for John: