Rumours intensified last summer when she shared pictures of herself in mo-cap gear on social media, sparking speculation that she could be seen playing a much older version of Peggy, given time travel is rumoured to be at play.
But asked at Ace Comic-Con whether Carter’s own standalone series Agent Carter could return, Atwell spoke about both that TV show and the Marvel big-screen movies.
“Well, I feel incredibly lucky to have been able to play a beloved character for so long, as is,” she said, via ScreenRant.
“It’s very unusual. I wouldn’t have thought starting off in my career that that would happen. You do one character for however many months and then you go and do the next.
“So I think it’s an unusual position to be in – it would be very unusual to have the choice to do that again.”
She added: “I think the main thing, though, is if it were – if there were interest in Netflix or in her being in a film or something – that it would have to feel right.
“I wouldn’t want to go over old ground. It would have to be new, there would have to be higher production values so she could do more. I’d have to feel like it’s not just, you know, ‘a case a week with Peggy Carter.’
“If she’s had an impact on audiences, let that impact grow, so it delights them, but I think it should be to do with more of the current climate now.
“What are smart issues to bring up? How to create any sort of kind of social weight, an emotional kind of gravitas to the show.”
Agent Carter had two seasons, totalling just 18 episodes running from 2015 to 2016.
Atwell has also played the character in Captain America: The First Avenger, Captain America: The Winter Soldier and Avengers: Age of Ultron.
Emily VanCamp played her great-niece Sharon Carter in Captain America: The Winter Solider and Captain America: Civil War.
Avengers 4 is out next year.