Just when you thought you've seen it all on the tube, the annual No Trousers on the Tube day rears its head, startling London commuters.
Hundreds of pranksters left their trousers and skirts behind to casually board London Underground trains on Sunday (December 8) in underwear, all in the name of fun.
Those baring all were asked to remain calm, and pretend like nothing was different as part of the challenge.
Passengers reacted in true London fashion as the participants poured in, with some refusing to acknowledge the eyebrow raising event and others taking photographs.
Social media saw residents in the capital divided over the decision, with some proudly advertising the part they played.
Some travelling saw the funny side of hundreds braving the cold to get involved.
Others, however, were less partial to the celebration of freedom, with one tweeter describing how no trousers day makes her queasy.
She wrote: "I don't want to see unknown men displaying their junk. Any girl doing it is daft."
The yearly No Trousers on the Tube celebration stems from a New York prank in 2002 and has since spread to other cities as an annual celebration of silliness.
The event took part ahead of a 24-hour strike beginning on the underground on Sunday evening.
Vancouver, Prague, London and Milan are just a few of the world's capitals which have embraced the act, be it in the rain or during sunny conditions.
One participant wrote in the event's Facebook group: "I am keen to start a monthly event!"
Watch this space, commuters.
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