In this Christmas special, Romesh Ranganathan, Rob Beckett and Tom Allen are locked overnight in the world-famous toy shop Hamleys, on London's Regent Street.
With no security guards or grown-ups there to hamper the fun, the trio can run wild for the night and do all the things they dreamed of doing in a toy shop when they were kids.
It's Night at the Museum meets Big: the celebs run amok, raid the shelves, chat about Christmas, invent daft games to play and reminisce with funny festive stories, as they hang out after hours and unsupervised in the fun emporium.
The rules are: sleeping's cheating, leave it how you found it, and if you break it, you pay for it! They can do anything they like, as long as they're out of the store before the cleaners arrive and the shutters go up the next morning.
One Night In Hamley's airs Christmas Eve at 9pm on Channel 4.