"Rich Kids of Beverly Hills" star Dorothy Wang celebrated her Dirty Thirty along with her closest friends, including John Mayer.
Wang's birthday party went down Thursday at Delilah in West Hollywood. Mayer showed up with Wang in her party bus, along with E.J. Johnson and Ben Baller.
Baller and Wang are actually connected ... they have the same birthday.
Mayer and Baller have been close for years, but the "Your Body Is A Wonderland" singer ended up leaving with Wang at the end of the night.