Foo Fighters star Dave Grohl is thought to have broken his leg after falling off the stage during a concert in Gothenburg, Sweden.
The band were two songs into their set at the Ullevi stadium when the singer went to jump on a ramp but missed and fell into the security area.
"I think I just broke my leg," Grohl told the crowd as he lay on the ground.
"I'm going to go to hospital. I'm going to fix my leg. And then I'm going to come back."
He added: "You have my promise right now that the Foo Fighters - we're going to come back and finish the show."
Eyewitnesses told the BBC that the band continued the concert, playing cover versions whilst Grohl sought medical attention.
Keiron Brennan 43, from London, filmed the moments just after the 46-year-old frontman toppled from the stage.
He said: "We were only around 200 yards away and at first we thought it was a prank but then it became apparent that it was quite serious. The drummer went ashen and jumped down to see where he was. Everyone was worried as we were only two songs into the gig and we couldn't see what had happened to him.
"He reappeared after an hour to continue the concert, sitting in a chair with his leg bandaged.
"It was surreal to see him perform on stage with a medic holding his leg. The crowd was just amazed that he was carrying on. He was just phenomenal. I can't see how he will make the next gig in Holland but then he's more of a man than I am so I wouldn't put it past him," he added.
Grohl fell at 21:00 local time (20:00 BST) and went on to perform for another two-and-a-half hours.
His band later tweeted a picture of what appears to be an x-ray of his leg.
The Foo Fighters are due to play their next concert on Sunday at the Pinkpop festival in the Netherlands, followed by two dates at Wembley Stadium in London next weekend and then a headline set at the Glastonbury Festival on 26 June.
A statement on the Wembley website said: "We are aware of the incident last night involving Dave Grohl and are in contact with the event organisers, who at this stage have no further information.
"As soon as we have news from the artiste this will be made public."
This year has seen several musicians injured on stage.
Madonna also fell off stage during a live performance at the Brit Awards. The pop star continued her performance, but said she suffered "a little bit of whiplash".