'Avengers: Infinity War' Star Sebastian Stan Describes The Day He Found Out What Was Happening to Bucky

Fans are still reeling from the end of Avengers: Infinity War, when Thanos' simple finger snap [...]

Fans are still reeling from the end of Avengers: Infinity War, when Thanos' simple finger snap wiped out half the universe and many fan-favorite superheroes from the Marvel Cinematic Universe.

The actors in the new Avengers movie have spoken at length about how secretive the filming process was, and how they didn't have full scripts for the movie to protect its secrets. But some actors had to show their character's deaths, including Sebastian Stan.

While speaking during a spotlight panel at Wizard World Philadelphia over the weekend, Stan spoke about the day he found out about Bucky Barnes' fate in Avengers: Infinity War.

"I remember the day on set and James Young, who is one of my talented, glorious stuntmen … on this film, came up to me and told me what was happening," Stan said to the audience.

Stan said that Young explained filming the scene when he was going to disappear very nonchalantly, saying there was a mat he'd fall on top of before fading from existence and that the directors Anthony and Joe Russo would further explain it.

"Oh, OK," Stan said stunned, prompting laughs from the crowd.

"And I was like, 'maybe this is it.' And I remember Anthony was talking to everybody, and I was like, 'Anthony, do- OK, I'll wait. Uh, do- am I- uh, is this it?'

"And he was like 'No, well, you know, maybe. But not really. Well, I don't know.' So, that's the way that day went."

Stan added that he had to ask if the same thing happens to Anthony Mackie, and was satisfied when the filmmakers told him the Falcon actor was definitely gone too.

Avengers: Infinity War served up many devastating character losses, and fans are going to have to wait to see how it all plays out when the untitled sequel premieres next year.

While no one knows the plot of Avengers 4 or its official title, there are rumors that have been suggesting time travel could be involved, especially after Thanos demonstrated how fluid time is with the power of the Infinity Stones.

The latest theory posits that Tony Stark goes back in time and interacts with Loki, Captain America, and Thor during the time of the original Avengers film, though it remains to be seen if he's able to alter the future and prevent those deaths from occurring.

Avengers: Infinity War is now playing in theaters.