Lake agreed to sing on the recordings for "In the Wake of Poseidon" (negotiating to receive King Crimson's PA equipment as payment). Eventually, he ended up singing on the band's early 1970 single "Cat Food" (the flip side was "Groon") and on all but one of the album's vocal tracks. The exception was "Cadence and Cascade", which was sung by Fripp's old schoolfriend and teenage bandmate Gordon Haskell. There does exist however, an early mix of the song with Lake singing a guide vocal which was unearthed and featured on the DGM site as a download. At one point, the band considered hiring the then-unknown Elton John to be the album's singer, but decided against it. Other former members and associates returned – as session players only – for the Poseidon recordings, with all bass parts being handled by Peter Giles and Michael Giles drumming. Mel Collins (formerly of the band Circus) contributed saxophones and flute. Another key performer was jazz pianist Keith Tippett.