One Direction star Niall Horan was hit in the knee by a thrown object on stage during the group’s Amsterdam show. The 20-year-old singer, who had a major knee surgery earlier in 2014, continued to perform despite bleeding.

Together with his bandmates (Harry Styles, Zayn Malik, Liam Payne and Louis Tomlinson), the Mullingar, Ireland native was singing on stage for their “Where We Are” tour in Holland on Wednesday night when an overzealous fan threw an object on stage, hitting Niall in the knee.

Niall proved to be a professional, though, and still continued to sing despite suffering from pain and bleeding. He was caught on camera limping on stage after their number.

Vine video by user diego ok.

After the show, the singer thanked their Amsterdam fans for being “one of the loudest one direction crowds yet!” but also begged them to be careful on what they throw at them on stage.

“Also guys! Can you limit what gets thrown on stage please! Coz somethin thrown at me tonight! Hit my knee! A lot of pain from it,” Niall tweeted.

“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”

Click here for the photo of Niall’s bleeding knee.

As he pointed out, he underwent a major knee surgery in January. Fans were initially unaware of the operation until Niall appeared with crutches at the BRIT Awards.

He wasn’t the only One Direction singer to have been hit by a flying object on stage. Harry was smacked on the face by an unknown item, presumably thrown by another eager fan. Although the hit must have hurt him even just a bit, Harry just shook it off and continued walking.

Vine clip from 1Dxclusive Clips