Mariah Carey's twins Moroccan and Monroe help her sing All I Want For Christmas Is You She is the undisputed Queen of Christmas. And on Wednesday Mariah Carey recruited her little prince and princess Moroccan and Monroe to help sing her hallmark holiday anthem. The 49-year-old shared a sweet video of herself teaching her twins the harmonies to her 1994 yuletide smash All I Want For Christmas Is You. As the trio traveled together in the back of a limo, Mimi instructed the driver to turn it up as she led her brood in the vocals. The siblings, wearing Santa hats each, were like the rest of the world clearly not yet sick of the irresistible earworm, enthusiastically bouncing around as they blasted out the backing vocals. A lot of people are mad at Mariah for not having the kids wear seatbelts. 'Roc & Roe have been practicing the background vocals to "All I Want For Christmas Is You", we're gonna take this one step at a time - we're very excited about it!' Mariah captioned the clip