The star-studded cast of "Oppenheimer" left the film's London premiere early on Thursday as the Hollywood actors' union staged its first major strike in more than 40 years.

Emily Blunt, Matt Damon, Cillian Murphy and Florence Pugh walked the red carpet outside the ODEON Luxe Leicester Square cinema Thursday, but then exited before the movie's showing, director Christopher Nolan told the audience inside the theater.

"We have to acknowledge, you've seen them earlier on the red carpet," Nolan said of the actors. "Unfortunately, they're off to write their picket signs for what we believe to be an imminent strike by SAG (Screen Actors Guild), joining one of my guilds, the Writers Guild, in the struggle for fair wages for working members of their union."

After months of negotiations with Hollywood studios failed to achieve a new film and television contract, SAG-AFTRA, which has approximately 160,000 members, went on strike Friday at midnight on the West Coast, joining about 11,000 members of the Writers Guild of America who have already been on the picket lines since early May.

It marks the first time since 1960 that both Hollywood's actors and writers have been on strike simultaneously.

The Screen Actors Guild last held a strike in 2000 over its commercials contract, but this is the first time it has struck over its film and television deal since 1980.

According to the union's strike rules released Thursday, actors are not allowed to promote their work through premieres, interviews, personal appearances, conventions, fan expos or festivals. 

Speaking to Deadline on the red carpet prior to leaving the premiere, Damon said he supported the decision to strike, but acknowledged that it would also be "brutal for our sister unions," including the International Alliance of Theatrical Stage Employees, IATSE, which represents tens of thousands of below-the-line film and TV workers, such as editors, camera operators, set designers and grips.

"Nobody wants a work stoppage," Damon said. "But if our leadership is saying that the deal isn't fair, then we gotta hold strong until we get a deal that's fair for working actors. It's the difference between having healthcare or not for a lot of actors. And we've got to do what's right by them."

Among the sticking points for both actors and writers are residuals from streaming services and the use of artificial intelligence.

The Alliance of Motion Picture and Television Producers, the group which represents all the major Hollywood studios — including CBS News' parent company Paramount — said in a statement that the strike was "the union's choice, not ours."

In a news conference Thursday, SAG-AFTRA President Fran Drescher criticized the studios, saying they "plead poverty, that they are losing money left and right, while they give millions to their CEOs. They stand on the wrong side of history at this very moment." 

In:
• Hollywood
• Screen Actors Guild
• Strike