(AFP) - A new Beatles song, produced with the help of AI, is on track to be named number one on the UK's official singles chart on Sunday night, the chart company said.

The song, "Now and Then", that used artificial intelligence to include the vocals of John Lennon and guitar by George Harrison, who died in 1980 and 2001 respectively, was released last Thursday.

"Now And Then debuted at Number 42 in the UK last week based on just 10 hours of sales, but is now expected to jump 41 places to the top of the Official Singles Chart when Friday’s chart is announced on BBC Radio 1's The Official Chart," Official Charts said.

The song is set to be the Fab Four's 18th UK chart-topper and their first in 54 years, since The Ballad of John and Yoko in 1969.

The Beatles remain second to Elvis Presley, who has scored 21 number ones on the chart since his first hit in 1957.

"Now and Then" is currently ahead of the song "Standing Next to You" by Jung Kook, and last week's number one, "Is it Over Now?" by Taylor Swift, according to the chart which is based on preliminary sales and early streaming reports from key distribution channels in the UK.

Despite being highly anticipated, "Now and Then", which comes more than four decades after it was originally recorded as a demo by Lennon, received lukewarm reviews from music critics after its release.

"'Now and Then' is not terrible... But ultimately, it's kind of mundane," wrote Geoff Edgers in the Washington Post.

The Times daily in the UK said the song showed AI being used to its best advantage.

Parts of it also conjured up "that classic, bittersweet, Beatles-esque flavour", wrote reviewer Will Hodgkinson.

"Unfortunately, none of this can mask the fact that the Last Beatles Song is far from a lost masterpiece," he added.

- AI solution -

"Now And Then", first written and sung by Lennon in 1978, was finished by his fellow band members Paul McCartney and Ringo Starr.

The track was unveiled by Apple Corps, Capitol and Universal Music Enterprises, with a music video debuting on Friday.

McCartney, 81, announced the song's release in June, in what was dubbed in a promotional trailer "the last Beatles song".

"Now And Then" was one of several tracks on a cassette that Lennon had recorded at his home in New York's Dakota Building in 1979 -- a year before his death.

It was given to McCartney by Lennon's widow Yoko Ono in 1994.

Two other songs, "Free As A Bird" and "Real Love", were cleaned up by the producer Jeff Lynne, worked on by the other former Beatles, and released in 1995 and 1996.

An attempt was made to do the same with "Now And Then" but the project was abandoned due to background noise on the demo.

AI has now made it possible to extract the vocals from that recording, although the use of the technology in music is the subject of industry-wide debate, with some denouncing copyright abuses and others praising its prowess.

The two surviving Beatles finished "Now And Then" last year, including George Harrison's electric and acoustic guitar parts recorded in 1995.

© Agence France-Presse