An unreleased Beatles song, produced using artificial intelligence to recreate the voice of the late John Lennon, will be released this year, Paul McCartney has announced. In an interview broadcast by the BBC on Tuesday, the musician from the Liverpool band, who is about to celebrate his 81st birthday, explained that Lennon’s voice had been taken from an old cassette to make this new song. “We just finished and it’s going to come out this year.” This technology was indeed used to extract the voice of John Lennon from an old demo in order to complete a song.

The idea had already been considered a possible “reunion song” for the Beatles in 1995, when they were compiling their career-spanning Anthology series. Paul McCartney had received the demo a year earlier from Lennon’s widow, Yoko Ono. It was one of many songs on a cassette called For Paul that Lennon had made shortly before his death in 1980. The tracks were largely recorded on a boombox as the musician sat at a piano in his New York apartment.

The group also attempted to record Now and Then, a song that glorifies love and was fairly typical of Lennon’s later career, but the session was quickly scrapped. The recording had its fair share of technical problems due to the original version, which featured a persistent “hum” from the electrical circuits present during Lennon’s recording.

Paul McCartney spoke to the BBC at a new book launch and photography exhibition. Titled Eyes Of The Storm, the project features portraits taken by Sir McCartney on his own camera, between December 1963 and February 1964, when the Beatles were on the rise.