In 1968, The Beatles released Yellow Submarine, their fourth film. While they enjoyed the process of making their first movie, A Hard Day’s Night, working on Help! hadn’t been as enjoyable, and Magical Mystery Tour had been a disaster. They did not want to work on a new film, but their contract with United Artists required it. They saw the film as an annoyance, but they hardly had any involvement with it.The Beatles had a three-film contract with United Artists, meaning they had to produce a third film even if they didn’t feel like it. As a result, they put out an animated movie, fulfilling their deal without having to act on screen. They didn’t even voice their characters. The band appeared, unanimated, in one scene to fulfill their contractual obligation. Otherwise, actors voiced them.
Source: Emma McKee/Emma McKee