I spent a few hours this afternoon interviewing people associated with Preacher, AMC's adaptation of the beloved — and seemingly unadaptable — '90s comic book series. (My review of it is here.) One of those was with the show's leading man, Dominic Cooper, who already has experience in the comic book adaptations world through his role as the young version of Howard Stark in various Marvel movies and TV shows.

The bulk of our conversation (which I'll publish down the road) was about Preacher, and the larger issue of how a classically trained actor who didn't read comics growing up keeps winding up in filmed versions of them, but at one point the talk pivoted to Howard Stark — who, in the older version played by John Slattery, is a major part of the plot of Captain America: Civil War — and something unexpected occurred:

Cooper asked me to spoil the movie for him.

And I did.

This is what happened.

(The rest of this post will, of course, contain major spoilers for Captain America: Civil War, so read at your own peril.)

If Agent Carter had been renewed, was there any talk that you might still be able to pop by there now and then, or was your time on that show done?

Dominic Cooper: I didn't know. That was a wonderful treat that appeared every now and then. Because I adored playing Howard Stark. It was such a gift to even entertain playing him again, after realizing that the film franchise had moved into the future. It's almost impossible to know how Howard could be there, unless he creates some kind of potion to stay younger longer.

Have you ever met John Slattery?

Dominic Cooper: I haven't. He's great. He always says nice things about me, and I always say nice things about him, but we've never met. I hear he has quite a bad end in the latest one.

No, it does not work out well for old Howard.

Dominic Cooper: That's a shame. How's he die?

Bucky kills him.

Dominic Cooper: Sebastian Stan kills him?

He and his wife are going to the airport, and Bucky has been sent to assassinate them both.

Dominic Cooper: (eyes go wide) Wow. Wow. Bucky kills Iron Man's dad?

And that becomes the source of the final conflict in the film, as Iron Man finds this out and is not happy.

Dominic Cooper: Who wins? Cap sticks up for Bucky?

Cap sticks up for Bucky, and after Iron Man loses, there's a great moment where he tells Cap something like, "You're using the shield my father gave you. Give it back."

Dominic Cooper: Iron Man wants the shield back?

Yeah, because you made it.

Dominic Cooper: I made it. I remember. Because it's made out of vibranium. (laughs) I even remember the product I used. Wow.

It's a very good movie. Even though I've now spoiled a lot of it for you.

Dominic Cooper: (laughs) Yeah, you completely ruined it. You've prevented me from seeing it! And I was really excited! (puts his face in his hands) Oh, no! And I'm dead!

Alan Sepinwall may be reached at sepinwall@hitfix.com

Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "TV (The Book)" about the 100 greatest shows of all time, is available now. He can be reached at sepinwall@hitfix.com