Harry Styles has set social media alight by cutting his hair.

The pop star, who is on hiatus from boy band One Direction, stunned fans and followers on Friday (06May16) when he posted a photo of someone holding a ponytail on Twitter.

Fans immediately knew the tattooed hand and the hair were his.

"Whoops. #Littleprincesstrust", he wrote in the accompanying caption, suggesting the singer was donating his famous tresses to organisers at the Little Princess Trust, who make wigs for young cancer sufferers without hair.

Harry has yet to comment further on his haircut or post shots of his new look online, but the very thought of Styles' new style has fans raving.

One fan tweeted: "You realize how selfless and caring @Harry_Styles gesture is?! This man is an actual angel", while another added: "u never appreciate how truly beautiful life is until harry styles cuts his hair."

The new haircut could very well have been for his first big acting gig, after landing a role as a soldier in director Christopher Nolan's forthcoming World War Two epic Dunkirk.

The film will tell the story of how in 1940 British soldiers were shipped across the English Channel in a mass evacuation which saved them from being captured by Nazi troops, and in preparation for the shoot, the 22-year-old will reportedly have to live on a ship without running water to experience the conditions World War Two soldiers faced.

The Steal My Girl singer will spend several days living with his co-stars Tom Hardy, Mark Rylance and Kenneth Branagh on the vessel, which will be moored in a secret location of the South coast of England.