According to HeatVision Atwell screen tested for the role in London last week and impressed the creative team and was then offered the role. Atwell joins the recently announced Chris Evans as Captain America himself, Sebastian Stan as Bucky, and Hugo Weaving as Red Skull.
During World War II Peggy Carter serves with the Resistance in France, and though Peggy is nominally ‘the love interest’ I’m guessing Joe Johnston will be looking for something a little more feisty from her in this film.
Several UK TV roles led Atwell to be cast in Woody Allen’s Cassandra’s Dream, and she shared the screen with the aforementioned Ms Knightley in the 2008 film The Duchess. She’s certainly not as well known as the other three contenders but this may act in her favour when she takes to the screen in one of the biggest superhero movies yet.