Stewart, 81, who will serve as one of four cover models, along with singer Kim Petras and actresses Megan Fox and Brooks Nader, will be the oldest model in the long-running special edition magazine's history.
“When I heard that I was going to be on the cover of Sports Illustrated Swimsuit, I thought, 'Oh, that’s pretty good, I’m going to be the oldest person I think ever on a cover of Sports Illustrated,'" Stewart said via SI.com. “And I don’t think about age very much, but I thought that this is kind of historic.”
Stewart said she was motivated to participate in the pictorial in order to show that women can look good and feel great at any age.
"Age is not the determining factor in terms of friendship or in terms of success, but what people do, how people think, how people act, that’s what’s important and not your age,” Stewart said via SI.com.
Stewart's photoshoot took place on the white-sand beaches of Capa Cana, a private community in Punta Canta in the Dominican Republic and was shot by photographer Ruven Afanador, who she said was "so much fun" to work with.