Ariana, 26, agreed to collaborate on Idina's feminist Christmas song 'How About a Hand for Mrs. Claus' and Idina, 48, says the whole experience was incredible.

She told Billboard: "Ariana was so generous in her crazy touring schedule to find time to record this song with me, and I'm indebted to her.

"She would send me like every two lines that she recorded, and she would send like a little voice memo and go, 'How's this? Do you want me to do a riff here?' And I'd say, 'Just be you! I don't care, you're Ariana Grande!' And she'd say, 'No, I want you to be happy.' And then she'd say, 'What if on this lyric...' And I'd say, 'Yes! That's great.' And then I said, 'Wait, we're going to put in eight extra bars of a drum fill just so there's room for you to do a crazy Ariana riff.' It was just so funny, and she'd keep sending me little MP3s of what she was doing and making sure that I was happy. Every time, I was like, 'I'm happy!'"

Idina also revealed she turned to her 'Frozen' songwriters to pen the track for her.

She explained: "That was written by Bobby and Kristen Lopez, who are the composers of all the 'Frozen' music. … So I called them and I was like, 'Would you guys write me an original song for a holiday album?' And they were like, 'Sure!' And Kristen came back and she was like, 'OK, I wrote you a feminist song, a feminist Christmas song that's called "How About a Hand for Mrs. Claus," because she never gets any respect.'"