The pregnant star was joined by opera singer mum Patricia on a US television Christmas special on Monday night.
She also performed with American Idol judge, Randy Jackson on ABC's Mariah Carey: Merry Christmas To You.
Carey and her mother sang a duet on her new album.
On working with her, she said, 'Many people know that my mother is a trained opera singer, so I guess it was only a matter of time before we both got onto a record together.
'It was a lovely experience being in the studio together, and I'm very happy that I have this documented for the rest of my life.'
The two teamed up to sing O Come All Ye Faithful/Hallelujah for the new disc, Merry Christmas II You, which they sang on the television programme.