Jedward were performing at a massive festival in Weston-super-Mare, in the west of England, when Edward took a tumble on stage...
The twin struggled on through another song before being taken to hospital. He's been told he's torn his knee ligaments and will need an operation.
Loads of other acts played at T4 on the Beach. Here's N-Dubz in action!
There were several X Factor acts performing, including Alexandra Burke.
It rained most of the day, but JLS braved the weather to belt out some of their hits.
Former X Factor semi-finalist Diana Vickers sang tracks from her number one album Songs From The Tainted Cherry Tree.
The rain didn't stop the Saturdays dressing up in their best summer gear for the event.
And if the rain wasn't enough, the crowd had to put up with Tinie Tempah spraying them with a water pistol!!
T4 on the Beach has been going on every year since 2003. This year, Pixie Lott was one of the highlights, playing tracks including her recent hit, Turn it Up.
The crowd went crazy for Dizzee Rascal, who played Bonkers, Dirtee Disco and Holiday, and was joined on stage by Daniel Johnson from X Factor 2009.