Hi DR,
There are several different versions of who people refer to as the "5th Beatle", depending on who you ask.....
en.wikipedia.org
"Preston is one of very few musicians to be given a credit on a Beatles recording, which was done at the band's request; the group's 1969 single "
Get Back" was credited as "The Beatles with Billy Preston". He is one of several people referred to as a
fifth Beatle."
Further, , , , depending on which Beatle ya asked, it appears there was a whole cadre of "fifth Beatles"
"The band's members have offered their own views as to who should be described with the title. McCartney said in a 1997 interview that "if anyone was the fifth Beatle", it was manager
Brian Epstein,and later applied the honorific to producer
George Martin in a 2016 memorial post. Harrison said at the Beatles' 1988 induction into the
Rock and Roll Hall of Fame that there were only two "fifth Beatles":
Derek Taylor, the Beatles' public relations manager, and
Neil Aspinall, their road manager-turned-business-executive. Others referred to as the "fifth Beatle" include their early drummer,
Pete Best, original bassist
Stuart Sutcliffe, and keyboardist
Billy Preston."
..... Like I said, I know all about the "5th Beatle" thing