The team of Christopher Nolan’s Oppenheimer, including its cast members Cillian Murphy, Emily Blunt, Matt Damon and Sir Kenneth Branagh, left the London premiere early in order to  “go and write their picket signs” ahead of a strike by Hollywood’s largest actors’ union.

Cilian Murphy, Emily Blunt, Florence Pugh, Matt Damon and Rami Malek walked the red carpet an hour earlier than scheduled to join the walkout. The US actors union Screen Actors Guild-American Federation of Television and Radio Artists (SAG-AFTRA) had announced its first major members strike in over 40 years, after a deadline to reach a deal ended. The strike resulted from the unregulated use of AI and increase in the streaming services.

Addressing the cast’s walkout, Nolan said, “I have to acknowledge the work of our incredible cast, led by Cillian Murphy. 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, and we support them.”

Oppenheimer is set to release in theatres on July 21.