Mariah Carey's twins Monroe and Moroccan play back-up singers to their famous mother on her new Christmas song.

The 47-year-old songstress posted a reveal of nativity-inspired song The Star, featured in a new Sony Pictures Animation movie of the same name, inspired by the traditional Christian narrative, on her Instagram account.

The undisputed queen of the Christmas song, famous for her holiday hit All I Want For Christmas Is You, enlisted her little helpers, six-year-old Monroe and Moroccan, in another bid to top the yuletide charts.

The twins can be heard singing along with a children's choir to the words, "Follow your heart, it's Christmas," before their mother sings "Follow that star above you/ Should the world try to break you down/ There is one who waits for you/ Though you can't see him now/ Thunder and rain surrounds you/ But His love's just a breath away."

Mariah teased the children's involvement when she posted a picture on social media of the three of them in their pajamas, captioning it: “Hanging with my two best friends, listening to their guest appearance on #TheStar”.

The Star movie follows the adventures of a donkey named Bo as he becomes an unlikely hero during the first Christmas in the film, which features the voices of actors including Steven Yeun, Kristin Chenoweth, Zachary Levi, Gina Rodriguez, Tyler Perry, Keegan-Michael Key, and Ving Rhames.

The soundtrack also features Zara Larsson, Pentatonix, and Fifth Harmony, who will be contributing new song Can You See.