Justin Bieber was left nursing a sore head when a joke went wrong on Thursday (20May10) - he hit his face on a revolving door.
The Baby hitmaker was clowning around as he left a hotel in Germany but stumbled and smashed his head into a glass door.
The teen was caught on camera screaming, "Ow, ow!" at his aides - but soon saw the funny side.
He says, "I just walked into that door. My forehead hurts. I thought what happened was I pushed and it (the door) opened but obviously it didn't and I walked right into the window."