Sebastian Stan says he still has not seen Avengers: Doomsday and thinks it will be heartbreaking

Sebastian Stan is returning as Bucky Barnes in Avengers: Doomsday, but he says he is just as in the dark as everyone else about how the film ends. The Marvel actor has not seen the movie, does not know how it turned out, and already thinks fans should brace for heartbreak.

Stan said he has not watched the finished film and does not know how it landed. Even so, he told Decider he is sure it is going to be "probably heartbreaking" in a lot of ways, before adding, "We'll see who makes it to the next level."

That line has already given Marvel fans plenty to talk about, with some taking it as a possible clue that several well known characters could be killed off in the Endgame follow-up.

For Stan, one clear part of the experience was getting back together with familiar faces. He said he got to reunite with everyone on set and called the experience nostalgic, looking back on how many years they have known each other and grown up together. He also said the cast has been like a family, and that it never stops feeling that way.

Even the cast does not fully know the story

Stan is not the only Doomsday star to admit the film's plot is hard to pin down. Alan Cumming, who is reprising Nightcrawler, recently said he does not fully understand the story either. Cumming first played the mutant hero in 2003's X2: X Men United, and he also said most of his scenes for Doomsday were shot in front of a blue screen.

One possible reason is how Joe and Anthony Russo approached the screenplay. Joe Russo said last month that they see the script as a living organism. He said they are improvisation based and rehearsal based directors who like to discover what actors bring to their characters, and that sometimes they do not even get the actors until a few days or a few weeks before shooting them.

Stan has been part of the Marvel world since Captain America: The First Avenger in 2011, and later appeared in Captain America: The Winter Soldier, Captain America: Civil War and Avengers: Infinity War, among other films. His latest movie, Fjord, arrives in theaters Friday. Avengers: Doomsday is due in cinemas on Dec. 18.