When the late Stephane Grappelli recently turned up in EMI's vaults lurking on Pink Floyd's Wish You Were Here, it was likened to finding The Holy Grail. Grappelli had been working in Abbey Road Studios at the same time as the Floyd and was asked to come in and play with the band. Upon the album's release they said he'd been lost in the mix; more likely Gilmour and Waters had a fight about whose idea it had been and then dropped the veteran jazzer's deft solo altogether. Shame it's taken over 35 years to resurface.
(Grappelli comes in, beautifully, at 3:06)