'Long Shot': Seth Rogen and Charlize Theron Charm Crowd at SXSW Premiere

The screening at the Austin, Texas, festival ended with a surprise Boyz II Men performance.

Seth Rogen and Charlize Theron's new romantic comedy proved to be a crowd-pleaser at its SXSW premiere.

At the Saturday night screening of the offbeat film directed by 50/50 and Warm Bodies' Jonathan Levine, the audience at the Paramount Theater laughed, cried and cheered throughout the movie's two-plus-hour run.

In Long Shot, Rogen and Theron play an unlikely couple — she, a Secretary of State mounting a presidential run, and he, an outlandish Brooklyn journalist. But the unconventional pairing seems to have won over critics. "Suspend your disbelief and you may well be charmed," wrote The Hollywood Reporter's film critic John DeFore.

Still, both stars and Levine claimed to be anxious about the debut. "I'm so fucking nervous to show you guys this movie," said Theron ahead of the screening. "I'm going to go get a drink." Rogen shook his head in agreement, adding, "Exactly," before the trio exited the stage.

Turns out they did exactly that. As the credits rolled past midnight, Levine stepped back onstage for what was expected to be a brief Q&A about the making of the film. But before the first question was even asked, he told the crowd he was going to stop talking. "I'm only going to get myself into trouble," he said. "I've been drinking the whole movie. I was nervous you guys were going to hate it." And then in a reference to a hilarious scene in the film, he said with a laugh: "Fucking Austin, man. You guys fuck me up. If anyone has Molly I'll take it right now."

He wasn't the only one who'd had a couple of drinks, either. When Theron was then asked to share a few words about her role in the film, she admitted, "I don’t know why I have a mic because I’m drunk, too." The theater broke out in uproarious laughter, cheering on Theron. She ended up pulling it together to explain why this role appealed to her.

"I usually die in my movies or kill people in my movies or get assaulted. This is not in my wheelhouse. But I'm always looking to do different things because I get bored and I don't want to do the same shit every time," she said. "And I have been a sincere, down to the core of my body fan of Seth Rogen's. Never in a million years did I think I would be in a movie with him so I am 'hashtag blessed.'"

The event concluded with Rogen introducing special guests Boyz II Men, who play a prominent role in the movie. The R&B group surprised the audience and came onstage to play two songs, the upbeat "Motownphilly" and slow-jam "I'll Make Love to You." And as if still in character, Rogen and Theron danced the night away to the right of the stage.