Mariah Carey is being accused of telling a “tall tale” over her claim she came up with ‘All I Want for Christmas’ as a child.

Her co-writer on, and producer of, the smash festive hit Walter Afanasieff, 64, poured scepticism on the singer’s claim she wrote the song as a child on her Casio keyboard.

Mariah’s former collaborator told the ‘Hot Takes and Deep Dives’ podcast: “We were both on the same page about how we wrote ‘All I Want For Christmas Is You’, there was never any alternate story until probably 10 years ago.

“When she started to hint at the fact that, ‘Oh, I wrote that song when I was a little girl!’ But why weren't you saying that for 12 or 13 or 15 years prior to that? So it just sort of developed in her mind.

“She doesn’t play anything, she doesn’t play keyboard or piano. She doesn’t understand music, she doesn’t know chord changes and music theory or anything like that.

“She doesn’t know a diminished chord from a minor seventh chord to a major seventh chord.

“So to claim that she wrote a very complicated chord-structured song with her finger on a Casio keyboard when she was a little girl, it’s kind of a tall tale.”

Walter, who won the 1999 Grammy award in the Record of the Year category for producing ‘My Heart Will Go On’ by Celine Dion, added he and Mariah, 53, came up with the 1994 track together while working on three original songs for her then-upcoming ‘Merry Christmas’ album.

The pair are credited equally on ‘All I Want For Christmas Is You’, and Walter did concede Mariah was largely responsible for the melodies and lyrics, while he was behind the music and the chords.

Mariah told Billboard in 2017 about the song’s creation: “I am proud of this song that I wrote basically as a kid on my little Casio keyboard.”

Then in 2019 she told Cosmopolitan magazine: “I just sat down, decorated a little tree and put on ‘It’s A Wonderful Life’ and tried to get into that mood.

“Then I sat in this small room with a keyboard and started doing little melodies and stuff. I was going over all the things I think about at Christmas time that make me happy and how to turn it around and make it into a love song.”

Walter said the same year that Mariah “definitely does not share credit where credit is due” when it comes to the track and said he and his family have been trolled by Mariah fanatics as a result of such claims.