David Harbour, who made his Marvel Universe debut in the 2021 film *Black Widow*, has finally opened up about his return in *Avengers: Doomsday*. The 50-year-old actor is renowned for his portrayal of Alexei Shostakov, also known as Red Guardian, in the MCU. His most recent appearance in the role was in the 2025 *Thunderbolts* film, led by Florence Pugh.
While giving fans an update on his involvement in the upcoming MCU blockbuster, Harbour confessed that he was initially "not convinced" when he first embarked on the project. In a candid conversation with *Screen Rant* at Rose City Comic Con, the *Stranger Things* star remarked, "I wasn't even convinced when we started, but this movie is going to be really good."
During the chat, the Golden Globe nominee lavished praise on the Russo brothers, the directors of the new *Avengers* installment, for their tireless efforts and exceptional talent. According to David, they possess "a special sauce. I don't even fully grasp it, but they just know how to pull off these kinds of things." He further elaborated on their past Marvel achievements, citing *Civil War* and *Infinity War*, and remarked, "There's something magical about the way they weave in comedy and drama, along with surprises, scale, and epic storytelling. It's simply incredible."
Harbour also divulged that he had never experienced a set quite like *Avengers: Doomsday* in his entire career. "It's just enormous," he exclaimed. Led by Robert Downey Jr., the highly anticipated action sci-fi extravaganza is scheduled for release on December 18, 2026.
