It’s been almost five years since the last episode of “Entourage” aired on HBO, and yet Monday night’s movie premiere felt like no time had passed as cast and crew gathered to celebrate at the New Regency in Westwood.

Producer Rob Weiss said the idea to do a movie really revved up when fans asked for more. He’s just happy that wish can finally be granted.

“We weren’t going to just make a movie to make a movie, but there was a real appetite for it to happen from the fanbase,” Weiss said. “At the end of the day, no matter what happens these guys made a great movie, and I couldn’t be more proud.”

Original cast members Kevin Connolly, Jerry Ferrara, Adrian Grenier, Kevin Dillon and Jeremy Piven flanked the show’s creator Doug Ellin and producer Mark Wahlberg while talent like Bob Saget and T.I., who’ve made cameos on the show, also lent their support.

“The shoot was pretty frenetic at times and also a bit of a party scene but I don’t want to get into that too much,” Saget demurred.

New to the “Entourage” universe and playing a fictional character was Haley Joel Osment.

“It made the experience so surreal after being a fan of the show for so many years to come on and play a part in it,” Osment said. “It’s also so much fun to play an original character instead of a cameo of myself, though I think fans still think I’m just playing myself in the movie.”

The Johnnie Walker was flowing (“Johnny Drama” bottles, especially popular) at the raucous after-party outside the New Regency, which was made to look like the nightclub from the fake movie Grenier’s character, Vincent Chase, directs in the film. Jane’s Addiction came on for a live performance of the show’s theme song “Oh Yeah” for the crowd.

Tobey Maguire caught up Connolly while Dillon, Ferrara and Grenier were seen taking photos with fans. In the throng were models Emily Ratajkowski and Nina Agdal and lots of athletes including Lakers’ forward Julius Randle, NCAA basketball player of the year Frank Kaminskyand Sacramento Kings’ Rudy Gay.