One Direction's Niall Horan has urged fans to "limit" items which are thrown on stage at concerts.
After a show in Amsterdam he tweeted: "Can you limit what gets thrown on stage please! Coz somethin thrown at me tonight! Hit my knee! A lot of pain from it!"
He added: "Never wana sound like I'm complaining! But only having my operation 5 months ago, I still get a bit of pain and I'm very scared about it."
Overall though he thanked the Dutch city for "a great couple of shows".
Online footage from the show revealed that Niall wasn't the only member of the hit band to suffer. Harry Styles was seen to flinch as an object hit him in the face at one point during the gig.