Some of the stars of the upcoming film “Oppenheimer,” including Matt Damon, Emily Blunt and Cillian Murphy, reportedly walked out of the movie’s London premiere as SAG-AFTRA called a strike.

The performers appeared on the red carpet at the promotional event for the buzzed-about film, which is poised to hit theaters July 21. But as SAG-AFTRA, the largest union for actors, called a midnight strike Thursday after contract negotiations with film studios failed, the entertainers exited the screening, according to multiple reports.

“We have to acknowledge, you’ve seen them here earlier on the red carpet. Unfortunately, they’re off to write their picket signs for what we believe to be an imminent strike by SAG, joining one of my guilds, the Writers Guild, in the struggle for fair wages for working members of the unions,” said Christopher Nolan, the film’s director, during remarks at the premiere. “And we support them.”

During a red carpet interview with Variety, Damon suggested the move by the film’s stars would happen, saying, “Look, if it’s called now, everyone’s going to walk obviously in solidarity.”

The union is demanding higher compensation and mandates to limit the use of artificial intelligence in Hollywood.

The SAG-AFTRA strike is poised to start two months after the Writers Guild of America’s members took to the picket lines over similar demands. It’s the first time since 1960 that both unions are on strike at the same time.