Now the singer and actor is releasing an album that will feature cover versions of the Swedish pop group's hits, and going on tour to promote it.

Dancing Queen, to be released next week, features Cher's interpretations of 10 of the band's songs, including SOS, Waterloo and Mamma Mia.

Cher, 72, said the idea came to her after she performed the song Fernando for the July 2018 sequel Mamma Mia! Here We Go Again movie, whose story is built around ABBA songs.

Cher played the wealthy celebrity mother of the character played by Meryl Streep, in what was the singer's first on-screen role in eight years.

"I did Fernando and then I did the opening to Super Trouper', Cher told Reuters Television.

"Somehow, it came from that ... I was going to go off on vacation and I just thought that might be a cool thing to do," she said of the new album.

Cher said she had been advised not to include versions of Mamma Mia and Waterloo on the album because the originals are so well-known.

"And I went, nah, I love them. I don't care how famous they are, I'm just going to do them, because I want to do them, because I want to be able to sing them," she said.

As well as embarking on a US tour in January, Cher is also co-producing a musical based on her 50 years in show business, which have been marked by multiple comebacks. The show is due to open on Broadway in December.

It has not been easy, she said, to watch someone else play out her life story on stage.

"It's not fun at all. And the more honest you are, the worse it is. First time I saw it, I just walked out," she said.

Dancing Queen will be released in the US on September 28.

Australian Associated Press