When Newsround heard that Justin Bieber was in town, we sent our very own Bieber Cam to track him down.
The popstar was playing at Radio 1's Big Weekend in north Wales.
Bieber Fever truly arrived in Britain and lots of fans had t-shirts to prove it!
Justin played three songs from his hit album My World, finishing with Baby.
Ricky has more...
Video of the performance from BBC Three