On a WWF tribute lp No One's Gonna Change Our World (a line from Across The Universe). Recorded in '68 (the demo is on Anthology 2), released at the end of '69 with wildlife sound effects for the occasion. You don't get those on the Let It Be version produced by Phil Spector.
Beatles [on Let It Be]
Sloan Wainwright [Loudon's youngest sister]
Rufus Wainwright [in film I Am Sam; Sloan's nephew]
The "nothing's gonna change our world"-chorus came from two young fans, handpicked by Paul among the usual crowd in front of the Abbey Road studio gate, a first in the Beatles' career. Their names? Check out Mark Lewisohn's The Complete Beatles Chronicle.