The on-set photo released on Twitter Wednesday, features the actress enjoying a smoke alongside the caption "Hope."
Carter is taking over the role of Margaret from Vanessa Kirby who starred as Queen Elizabeth II's sister in the first two seasons of The Crown. The switch comes as the show continues to chronicle members of the royal family as they age.
"I'm not sure which I'm more terrified about -- doing justice to the real Princess Margaret or following in the shoes of Vanessa Kirby's Princess Margaret," Carter previously said. "The only thing I can guarantee is that I'll be shorter than Vanessa."
Netflix also released the first image of Ben Daniels as Margaret's photographer husband Antony Armstrong-Jones who was previously portrayed by Matthew Goode. Margaret and Armstrong-Jones were married in 1960 before divorcing in 1978.
"Hurt," the streaming service captioned the image on Twitter which features Goode holding up a camera.
The photos of Carter and Daniels come after Netflix released on Monday the first image of Olivia Colman as Elizabeth. Colman is stepping into the role following Claire Foy.
Production on The Crown Season 3 is currently underway.