Just when you think Justin Bieber might be growing up.

While on a self-imposed month off to relax with friends before working on his next album, Bieber was spotted in his underwear, hot tubbing with a buddy (also in his underwear).

What else? Bieber was pulled over by police in South Beach.

While TMZ reported he called for police protection from fans, it turns out the real reason for the stop was a bit more embarrassing — the cops thought he was too young to be driving a convertible Rolls-Royce.

He could barely see over the dash.

In other news, Bieber made a surprise visit to girlfriend Selena Gomez‘s concert on Saturday night, but had to make a hasty exit after nearly being mobbed by fans.

After word got out that Bieber was there, dozens of fans reportedly chased him as he tried to leave the venue through a back door.

What are these girls chasing? (see the photo above)