During the premiere of Christopher Nolan's highly anticipated film "Oppenheimer," the cast chose to show solidarity with the recently authorized strike by the Hollywood actors' union and walked out of the event.

Nolan confirmed their departure before the beginning of the screening at Leicester Square in London, according to trade publication Variety. The cast, which includes Cillian Murphy as the titular mastermind behind the Manhattan Project, as well as Matt Damon, Emily Blunt and Florence Pugh, had a plan to leave if the actors' union, SAG-AFTRA, called the strike amid the fanfare.

"We talked about it," Damon told Variety on the black carpet. "Look, if it's called now, everyone's going to walk obviously in solidarity ... Once the strike is officially called, (we're walking). That's why we moved this (red carpet) up because we know the second it's called, we're going home."

"There are a lot of people here we did not want to disappoint, but we're also in complete solidarity with our colleagues and what they're doing," co-star Kenneth Branagh added. "I know they've worked diligently to achieve an agreement which is happening at a critical point in our industry. It's important that we're ready to be shoulder-to-shoulder with them as the situation develops."

Indeed, with the work stoppage looming, the premiere was moved up an hour so that the cast could walk the carpet before the SAG board's announcement, the Associated Press (AP) reported. The premiere began just before 5:00 p.m. local time, Variety said, with publicists and marketing executives looking anxiously at their phones and watches.

Damon and Branagh were joined at the premiere by fellow co-stars Josh Hartnett, Tom Conti, Robert Downey Jr. and Rami Malek. The cast and crew posed for photos alongside Nolan and producer Emma Thomas minutes before the strike was called.

SAG-AFTRA's national board of directors on Thursday voted unanimously to approve the 160,000 actors comprising the union's membership. The move widened the scope of labor unrest in an entertainment industry that is already facing many headwinds and an ongoing strike among its writers.

The vote came after negotiations between the actors' union and the major studios – represented in labor dealings by the Alliance of Motion Picture and Television Producers – failed to reach an agreement on a new film and TV contract. The old collective bargaining agreement expired Wednesday night without a deal in place.

Much like screenwriters, actors have been battling studios for a deal that would deliver far better pay and residuals from streaming. That deal would also address other issues, such as the use of artificial intelligence, that have been reshaping the entertainment landscape.

The dual strikes – is shaping up to be an extraordinary standoff that historians and labor experts have attributed to a confluence of cohesion among Hollywood unions, a nationwide rise in labor activism after the COVID-19 pandemic and dramatic technological change.

"It's really about working actors," Damon told Variety. "It's $26,000 to qualify for health coverage and a lot of people are on the margins and residual payments are getting them across that threshold. This isn't an academic exercise. This is real life-and-death stuff. Hopefully, we get to a resolution quickly. No one wants a work stoppage, but we've got to get a fair deal."