Photo: BANG Showbiz - BANG Showbiz. All rights reserved.

Katy Perry crashed child's birthday party

Katy Perry made children cry after gatecrashing a five year old's birthday party.

The 'Dark Horse' hitmaker dressed up as a clown for the video for her track 'Birthday' and carried out a prank at a party, where she attacked a man with a pinata stick and staged a car accident, but the spoof incident left children in tears.

Eye witnesses told TMZ, Katy pranked a real birthday party and most of the guests had no idea it was a joke.

Children were crying and one woman "stormed away" visibly upset by her antics.

The hidden camera gag was shot at Knollwood Country Club outside Los Angeles and a video obtained by the website shows one little girl saying, "Mommy, I want to leave."

During an interview on 'Jimmy Kimmel Live', Katy spoke about going "undercover" at the bash, but didn't mention the fall out.

Speaking earlier this week, she said: "I just did a music video completely undercover as five of the world's worst birthday entertainers, because I was sick of making gorgeous music videos where I'm sexual."

Jimmy joked: "People are sick of that, yeah, really tired of looking at you."

Katy, 29, then previewed a clip of the video which sees her dressed as a clown drinking and burping, saying: "I'm not really a birthday party entertainer, I'm just trying to get some cash on the side," adding, "Happy birthday kids."