Harry Styles' fans got an eyeful when the singer flashed his underwear on stage.
The heartthrob was performing in London when his One Direction bandmate Liam Payne decided to play a prank on him - and sneaked up behind him and pulled down his trousers.
The crowd went wild as Harry stood on the stage in his small black pants, blushing as he tried to preserve his modesty.
As Harry, 19, tried to zip himself back up, his bandmates watched and laughed and the 20,000 fans at the O2 Arena cheered, screamed and whistled.
But the curly-haired star wasn't to be put off, and carried on singing the group's hit What Makes You Beautiful throughout.
It wasn't the first time Harry has been the victim of one of Liam's jokes - last year he tore open Harry's shirt and exposed his bare chest at a concert in the US.