"'Now And Then' is now available to listen to worldwide," The Beatles wrote on X, formerly known as Twitter.
The original track was recorded as a demo in the late 1970s, but remained unfinished. Many years after Lennon's death, other band members, Paul McCartney, George Harrison and Ringo Starr, returned to work on the song, which was eventually completed more than 40 years after being written.
To complete the song, they used artificial intelligence to extract Lennon's voice from the old demo. However, McCartney said that its new version would not contain anything created artificially.
An official music video for the song will be released on Friday.