Sebastian Stan expects Avengers: Doomsday to be "heartbreaking".

The 44-year-old actor will reprise his role as Bucky Barnes / Winter Soldier in the upcoming Marvel Cinematic Universe (MCU) blockbuster and, although he hasn't seen the picture, he is expecting it to tug at the heartstrings of audiences.

Stan told Decider: "I haven't seen the movie, and I don't know how it turned out.

"I'm sure it's going to be probably heartbreaking, in a lot of ways. We'll see who makes it to the next level."

Stan was delighted that he "got a chance to reunite" with his Marvel co-stars, including Chris Evans.

The Fjord actor said: "It was very nostalgic to look back, and think about all of these years that we've known each other, and grew up together. It's incredible in that way. It's been a family and it never stops being that way."

Meanwhile, Stan's Avengers: Doomsday co-star Alan Cumming admitted last month that he "doesn't understand" the plot of the movie, which will be released in cinemas in December.

The 61-year-old actor, who will reprise his role as X-Men mutant Nightcrawler, told SiriusXM: "To be honest, I don't fully understand the plot ...

"There was a bit when we were shooting a scene, and it was one of the rare scenes when I was actually on the backlot and not in front of a blue screen.

"And this man came and said: 'So right now Alan, these giant robots are blah blah,' and started to tell me the thing, and I was like: 'You know what, thank you so much, but just tell me where I point my, whatever I point. And I'll do that. Really, I just know I'm here to run around.'"

Meanwhile, Stan is set to portray Harvey Dent in The Batman Part II and has likened Matt Reeves' superhero sequel to the mafia epic The Godfather Part II, widely regarded as one of the greatest sequels in cinema history.

He told Variety: "I go to set sometimes and I look around and I'm like, I think we're making f****** Godfather Part Two. I feel that highly about it. Matt has spent three years working on it.

"There's a lot of speculation about these roles, about what this movie is, but I think it's going to be a good payoff - it's really grounded and real, and that's what I loved about it. You want to tease it a little, but we still have a long time."