Shortly after moving to New York in 1971, John Lennon and Yoko Ono became so paranoid that authorities were tapping their phones that they decided to record their conversations. More than 50 years later, a selection of these previously unheard recordings form what Kevin Macdonald describes as the "beating heart" of his new documentary, "One to One: John and Yoko," premiering in Venice on August 30.

In one conversation, Ono candidly describes what it was like to be blamed for the Beatles' breakup. In another, Lennon describes his idea for a U.S. tour that would raise bail money in every city they played, as well as trying to get Bob Dylan on board (and convince Dylan aggressor A.J. Weberman to leave the musician alone). Some of the film's most amusing moments feature an endless back-and-forth about Ono's attempts to acquire flies for a new art installation (obtaining flies too far in advance was considered inappropriate because, as one gallery owner noted, "the thing is, flies die every day.")

For Macdonald, the phone calls – along with a wealth of footage, including home movies as well as commercials and news clips from that period of political unrest – were crucial to making “a totally immersive archival film” and offer a surprisingly unique insight into one of the most famous cultural figures of all time.

“One to One” focuses on an 18-month period after Beatlemania, when the pair left a life of luxury in the United Kingdom to hole up in a relatively modest two-bedroom apartment in New York’s West Village. They immediately became figureheads for the counterculture and anti-Vietnam War movements, and contacts for almost any activist group that needed a little celebrity support.