David Harbour may have teased Russia's personal Avengers team receiving a cameo appearance in Marvel's Black Widow.

In a recent Instagram post, Harbour shared the Black Widow poster of his character Alexei Shostakov (aka Red Guardian), accompanied by a message hyping up the film's theatrical debut. "Ursa, Yelena, Nat, CD, Sputnik, I and all the rest of the winter guard look forward to sharing a popcorn bag and a big ole screen in a dark theater with ya on July 9," he wrote.

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While no other details were given about the "winter guard" line, the name holds a direct connection to Red Guardian in the comics. A Russian-based superhero team comprised of former Soviet super-soldiers, the Winter Guard's most notable members include the Nikolai Krylenko/Vanguard incarnation of Red Guardian, the armored Crimson Dynamo, bear shapeshifter Ursa Major, synthezoid Vostok (aka Sputnik) and Darkforce-wielding Darkstar. In addition to making comic appearances, the team has previously appeared in animated form on the Avengers Assemble and Marvel's Future Avengers cartoons.

Compared to Alexei Shostakov's comic status as Natasha Romanoff's former husband, Harbour's Red Guardian has been set up as a father figure to Natasha during her early years as a spy. The character has appeared prolifically across Black Widow's trailers, reuniting with Natasha, her Red Room "sister" Yelena Belova and Melina Vostokoff after they break him out of prison and even fighting antagonist Taskmaster in his Red Guardian costume. The most recent Black Widow trailer also features brief flashbacks of Alexei training a young blue-haired Natasha and firmly telling her, "My girls are the toughest girls in the world."

Initially meant to release in May 2020, Black Widow was delayed multiple times by Disney due to the coronavirus (COVID-19) pandemic. The film will mark Marvel's first theatrical entry in Phase 4 of the Marvel Cinematic Universe in 2021, followed by Shang-Chi and the Legend of the Ten RingsThe Eternals and Spider-Man: No Way Home.

Directed by Cate Shortland, Black Widow stars Scarlett Johansson as Natasha Romanoff/Black Widow, Florence Pugh as Yelena Belova, David Harbour as Alexei Shostakov/Red Guardian, O-T Fagbenle as Mason and Rachel Weisz as Melina Vostokoff. The film arrives in theaters and on Disney+ Premier Access July 9.

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Source: Instagram