More than 50 years after the Beatles broke up, Paul McCartney said artificial intelligence helped create one last Beatles song that will be released later this year.

The song was made using a demo with John Lennon’s voice, McCartney said in an interview with BBC Radio 4 that was released Tuesday. He did not give the title of the song or offer any clues about its lyrics.

“When we came to make what will be the last Beatles record, it was a demo that John had, that we worked on,” McCartney said. “We were able to take John’s voice and get it pure through this AI, so then we could mix the record, as you would normally do.”

Holly Tessler, a senior lecturer on the Beatles at the University of Liverpool, said Tuesday that there was speculation that the song might be “Now and Then,” a song Lennon composed and recorded as a demo in the late 1970s.

Lennon was fatally shot outside his New York apartment building in December 1980. His widow, Yoko Ono, gave the tape to McCartney as he, Ringo Starr and George Harrison, who died in 2001, were working on “The Beatles Anthology,” a career-retrospective documentary, record and book series.

Two other songs on that tape, “Free as a Bird” and “Real Love,” were later completed by the three surviving Beatles using his original voice recording and were officially released in 1995 and 1996.

It is unclear exactly how McCartney was using the latest demo and whether any new lyrics would be incorporated.

The use of AI technology to create music with the voices of established artists has raised a number of ethical and legal questions around authorship and ownership.

“We have absolutely no way of knowing, creatively, if John were alive, what he’d want to do with these or what he’d want his contribution to be,” Tessler said.

Over McCartney’s career, he has been quick to engage with new creative technologies, whether talking about synthesizers or samplers, she added.

“I think he’s just curious to see what it can do,” Tessler said of McCartney.