Today's the day that many Beatles fans have been waiting for.

This afternoon, the famous 'lost' Beatles song 'Now and Then' will be released, having been completed with the late John Lennon and George Harrison's input via the wonder of AI.

The song's accompanying music video will also debut today and was directed by Peter Jackson, the man behind the 'Get Back' series - but ahead of its premiere, a short documentary about the making of the song has been released.

It features narration from Paul McCartney and the voices of people like Sean Ono Lennon, as well as plenty of archive footage from Paul, George and Ringo in the studio in 1994, explaining how the song first took root - and then "sort of languished in a cupboard" after the remaining trio didn't quite know how to finish it.

The documentary explains how the technology developed by Jackson for 'Get Back' allowed them to separate John Lennon's voice from the song without the accompanying piano - which meant that they could finally mix the song the way they wanted to.

It's a beautiful film that certainly whets the appetite for 'Now and Then'.

Watch it below: