Mariah Carey’s co-writer says her version of how her Christmas hit was written is a “tall tale”

The guy who co-wrote Mariah Carey‘s “All I Want for Christmas Is You” apparently has some issues with the way that she’s described the song’s origins and is sharing his version in a podcast.

Speaking with the podcast Hot Takes & Deep Dives with Jess Rothschild, Walter Afanasieff — sometimes called Walter A — discusses his creative collaboration with Mariah, which resulted in hits like “Hero” and “One Sweet Day.” The two also worked together on her 1994 Christmas album, and Walter claims that at some point in the past 10 years, Mariah has changed her story.

He particularly takes issue with how Carey described the song to Billboard in 2017: “This song that I wrote basically as a kid on my little Casio keyboard.” Walter is calling B.S. on that.

“She doesn’t play anything, she doesn’t play keyboard or piano,” argues Walter. “She doesn’t understand music, she doesn’t know chord changes and music theory … 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.”

In a recent Amazon documentary, Mariah claims she wrote the melody and all the lyrics on a keyboard in her house, then brought it to Walter in the studio to get the right sound.

Walter disputes this by describing — in minute detail — how he played the music and the chord changes, while Mariah echoed the melody and came up with lyrics, going back and forth “like ping-pong,” he says. And after that, he claims, she would call him at all hours of the night, asking for his opinion on the lyrics.

And while Walter allows that Mariah is a talented and wonderful artist, he says her story just doesn’t add up.

(Walter’s version of how they wrote the song starts at 12:19 into the podcast)