Screaming crowds watched Take That switch on the Regent Street Christmas lights in central London.
Singers Gary Barlow, Mark Owen,and Howard Donald flicked the switch to help mark the countdown to Christmas and also pointed out that it was a special day for the band.
Owen said: "This is the first time we have been on stage together for four years. It is good to be here."
Barlow said his best Christmas present was a BMX bike when he was a boy, Owen said it had been a karate suit while Donald said a track by Nat King Cole had been his best festive gift.
This year's lights were themed around the film Night At The Museum: Secret Of The Tomb.
A wealth of entertainment, including performances by Union J, Jessie Ware and the Jersey Boys, were part of the event hosted by London's Heart breakfast presenters Jamie Theakston and Emma Bunton.
Children got the chance to meet some of their favourite movie characters including Skipper, Rico, Private and Kowalski from the upcoming DreamWorks animation Penguins Of Madagascar as well as Po from Kung Fu Panda and Toothless from How To Train Your Dragon 2.
Living statues from Night At The Museum: Secret Of The Tomb also came to life at sites across Regent Street, including Robin Williams's character Teddy Roosevelt, Steve Coogan's character Octavius, Dan Stevens' character Sir Lancelot, Owen Wilson's character Jedediah and Rami Malek's character, the Egyptian Pharaoh Ahkmenrah.