Teen stars have so much fun ... and Justin Bieber, girlfriend Selena Gomez and Ashley Tisdale are proving it!

The three singers and a group of friends appeared in a home video goofing off to Carly Rae Jepsen's song "Call Me Maybe."

Tisdale also brought in her new beau, Boys Like Girls' Martin Johnson, to join in on the fun.

Crazy kids! Click thru to see Carly's official music video.