How AI helped us hear the "final" Beatles song: "It's the closest we'll ever come to having John back in the room"

The beatles.

Today, The Beatles release their final song. 45 years in the making, Now And Then features vocals recorded by John Lennon in the '70s and extracted from a demo cassette using AI-powered stem separation technology. 

Thanks to advances in stem separation made over the past few years, Peter Jackson (maker of the Get Back documentary series) and a team of engineers were able to extract Lennon's vocal from the demo to be mixed into a new version of the song, featuring newly-recorded bass and drums from Paul and Ringo, and guitar parts George Harrison recorded in 1995.