Plot: You better watch out - it’s time for a star-studded Christmas special! The three teams joining Marvin and Rochelle Humes for this festive episode are popstars Una Healy and Kimberly Wyatt, presenters Gregg Wallace and Kate Thornton, plus Union J’s George Shelley with drag queen Kitty Scott-Claus. Who will jingle all the way to the Final Chart Rundown for a chance to win £10,000 for their chosen charity?