Paul McCartney had doubts about finishing The Beatles’ last song, “Now And Then.”

In an interview, McCartney said he questioned himself during the process, but knowing John Lennon would have loved the song kept him going.

“But every time I thought like that, I thought, wait a minute.” He explained, “Let’s say I had the chance to ask John, ‘Hey John, would you like us to finish this last song of yours?’ I’m telling you the answer would have been, ‘yeah!’

“Now and Then’s eventful journey to fruition took place over five decades and is the product of conversations and collaborations between the four Beatles that go on to this day.” The video’s description reads. “The long mythologised John Lennon demo was first worked on in February 1995 by Paul, George and Ringo as part of The Beatles Anthology project but it remained unfinished, partly because of the impossible technological challenges involved in working with the vocal John had recorded on tape in the 1970s.”

In addition to the song and documentary film, The Beatles also released a music video to accompany “Now And Then.” Watch the video here.