John Lennon is seen with the “Imagine” piano.

John Lennon felt a little embarrassed by his former radicalism, according to his last personal assistant.

Fred Seaman worked alongside the music legend from 1979 to Lennon's death at the end of 1980 and he reveals the former Beatle was a Ronald Reagan fan who enjoyed arguing with left-wing radicals who reminded him of his former self.

In new documentary Beatles Stories, Seaman tells filmmaker Seth Swirsky Lennon wasn't the peace-loving militant fans thought he was while he was his assistant.

He says, "John, basically, made it very clear that if he were an American he would vote for Reagan because he was really sour on (Democrat) Jimmy Carter.

"He'd met Reagan back, I think, in the 70s at some sporting event... Reagan was the guy who had ordered the National Guard, I believe, to go after the young (peace) demonstrators in Berkeley, so I think that John maybe forgot about that... He did express support for Reagan, which shocked me.

"I also saw John embark in some really brutal arguments with my uncle, who's an old-time communist... He enjoyed really provoking my uncle... Maybe he was being provocative... but it was pretty obvious to me he had moved away from his earlier radicalism.

"He was a very different person back in 1979 and 80 than he'd been when he wrote Imagine. By 1979 he looked back on that guy and was embarrassed by that guy's naivete."