Denis O'Dell was involved with the Beatles' career as an associate producer of A Hard Day's Night, their first film, and How I Won the War, in which John Lennon had an acting role. He was producer of the 1967 Beatles film Magical Mystery Tour and The Magic Christian (in which Ringo Starr had a starring role). He also helped with the production of Let It Be and some of the promotional videos for their singles, and was director of the film and publicity divisions of Apple.
It couldn't be said that he had a particularly strong or influential role in their affairs as their inner band of associates went, but he was one of the figures who helped out with the business side of their career. According to his memoir about his Beatles experiences, At the Apple's Core: The Beatles from the Inside (written with Bob Neaverson), he pushed hard to get them to act in a film version of J.R.R. Tolkien's The Lord of the Rings trilogy. He even flew to India where they were studying transcendental meditation with the Maharishi in 1968 to try and persuade them, and set up a meeting between director Stanley Kubrick, John Lennon, and Paul McCartney to discuss it, but the project didn't come to pass. He also helped organize an archive of Beatles film footage that eventually proved helpful in the making of what came to be the Beatles Anthology video project; hoped to set up a live television performance of the Beatles in the Edwardian gardens at Stowe Public School in Buckinghamshire; contributed ideas for possible locations for a live Beatles performance in Let It Be; and suggested Ringo as the co-star (with Peter Sellers) for The Magic Christian.
O'Dell resigned as a director of Apple Corps in mid-1969 to return to film production after the company had been taken over by Allen Klein. He might be best known to Beatles fans, however, through an indirect reference in one of the group's most obscure songs, "You Know My Name (Look Up the Number)" (the B-side of "Let It Be"). A couple of times, the song mentions a "Denis O'Bell," a lyric which, although one consonant away from his actual name, was clearly inspired by their acquaintance.