Richard Osman presents a Child Genius festive special as four of the show's most formidable past competitors take on four of the country's finest celebrity minds, in a test to see who has the brightest brains this Christmas. The celebrity team captain is comedian and actor Rob Delaney. Rob's joined by Channel 4 News presenter Cathy Newman, comedian Dom Joly, and journalist and broadcaster Janet Street-Porter. The Child Genius team features Rhea, the show's youngest ever winner; Mog, from Warwickshire, who has amazed in the past with his outstanding memory; mathematical whizz-kid Christopher; and nine-year-old Fabio, who has a passion for science. The tests includes spelling, maths and general knowledge. Only one team can be crowned Christmas champions - can the celebrities take on the Child Geniuses and win?