Now that Marvel Studios has finally confirmed that a “Black Widow” solo movie is coming out next year, some plot details are being revealed. Cast member David Harbour was about to let a little slip about his character’s history with Scarlett Johansson’s Black Widow and similarities to Chris Evans’ Captain America.

At San Diego Comic-Con, it was revealed that Harbour is playing Alexei Shostakov, also known as Red Guardian, a name familiar to Marvel comics fans. Black Widow and Red Guardian were estranged spouses in the source material. Harbour wouldn’t say if the two are lovers or exes, but he revealed that they definitely know each other.

“He knows Natasha well, they’ve had a lot of issues,” Harbour told the Hollywood Reporter. “They have a lot of history together and that’s what gets explored in this movie.”

The actor has explained that the Red Guardian was essentially Soviet Russia’s version of Captain America. He was designed to be a weapon during the Cold War. However, he isn’t quite the golden boy that Cap was. “He’s a lot more flawed and has a lot more problems. In that way, he’s very surprising,” he added.

Harbour told Entertainment Weekly that he’s excited to play such a layered character. “In a way he’s a super-soldier, but he’s also a very complicated guy. He has a lot of flaws, a lot of idiosyncrasies. It’s a very rich character,” he said.

Joining Johansson and Harbour are Florence Pugh, Rachel Weisz and O-T Fagbenle. Pugh confirmed speculation that she will play Yelena Belova, a sister of sorts to Black Widow. Expect them to have some intense fight scenes, but they have a love-hate relationship. Weisz’s Malena is someone who has been through the Black Widow program five times, so she’s pretty lethal too. Fagbenle’s Mason is a “fixer” who helps out spies and might have a little romantic tension with Nat.

“Black Widow” is set to hit theaters May 1, 2020.

Black Widow movie The "Black Widow" movie will dive into Natasha's (Scarlett Johansson) past. Photo: Marvel Studios