Frankly, the title “Fifth Beatle” is such a general one that it has its own Wikipedia page. Paul said it should’ve been Brian Epstein or George Martin if anyone. George said it was either Derek Taylor or Neil Aspinall. A New York DJ called Murray the K said that the amount of publicity he gave them merited him the title, supposedly given to him by George. And then there’s the other musicians. Stu Sutcliffe and Pete Best, of course. A couple of people who were suggested as replacements for one or the other of the main four in the days before the band broke up. Eric Clapton was brought in for “While My Guitar Gently Weeps,” which was apparently enough to get him suggested as a Fifth Beatle by some.
And then there’s Billy Preston. Apparently Paul rejected John’s suggestion that Preston actually be a real Fifth Beatle. (Apparently, Paul’s problem was that it was hard enough reaching agreements with just four.) However, he is one of the few people credited on a song as being “The Beatles with [person].” He was brought in during the Get Back sessions in part to defuse tension and in part because he was generally agreed to be one of the greatest keyboardists working in the industry at the time. If they were going to have a keyboardist on their album, they were by-Gods going to have the best.
Preston’s career does not begin and end with The Beatles, of course. At age ten, he was already playing organ to back up Mahalia Jackson. In 1958, he appeared in the movie St. Louis Blues, playing W. C. Handy as a boy. (The movie has a hell of a cast; I think I saw it when I was writing up Juano Hernandez, but it’s worth seeking out for practically everyone in it.) He was a child prodigy who made his way into the world of popular music singing “Blueberry Hill” with Nat King Cole on Cole’s TV show. At age eleven. At age sixteen, he was playing keyboards for Little Richard.
And if the best-known song he wrote himself was “You Are So Beautiful,” well, it’s still pretty well-known. He also influenced a ton of people. Stephen Stills overheard him saying that, if you couldn’t be with the one you loved, you should love the one you were with, and he wrote a song about it. He played keyboard with the Rolling Stones. He toured with Eric Clapton. He played piano on the Cash cover of “Personal Jesus.” He performed with Ray Charles and the Red Hot Chili Peppers. And, sigh, he’s in Blues Brothers 2000, and why not.
Meanwhile, there was his personal life. Whether he was bisexual or trying to stop being gay, it’s true that he did when he was younger have relationships with women. Apparently, he stopped trying after discovering his fiancée, Kathy Silva, in bed with Sly Stone. (She would go on to marry Stone onstage at Madison Square Garden.) He was, according to those close to him, deeply ashamed of his same-sex attractions, which may have been why he succumbed to drug addiction. His manager revealed that he’d been sexually assaulted as a child, that he’d long been ashamed of his sexual attraction to men. It turns out his deep religious feelings—which didn’t stop him from performing on an explicitly atheistic John Lennon song—caused him enormous guilt and shame and may have kept him from being happy.