The gypsy-themed celebration took place at the Revolve Beach House in Malibu on Saturday night.
The Canadian singer could not miss the event and arrived there in his customized Audi R8.
Julianne Hough, Nina Dobrev, Jaden Smith and Dylan O’Brien also attended the party.
During a recent appearance on Good Morning America, Selena agreed to address her relationship with Bieber, unlike her recent live interview in Chicago, where she ended the discussion abruptly.
“He and I have had such a history together,” she said. “I’ll always care about him and protect him if anyone tries to be mean.”
“I don’t feel like I’m settled yet,” Selena said about juggling acting and singing. “I’m just kind of focusing on my work. I feel like the moment I’m not working, I get bored and then I go crazy. I’m gonna keep going, I think.”