The actress, who stars in the Avengers franchise as S.H.I.E.L.D. Agent Maria Hill, revealed that she was diagnosed with ovarian cancer at age 25, while filming the third season of How I Met Your Mother.
"I had tumors on both ovaries," she tells the magazine, "and the cancer had spread into my lymph nodes and surrounding tissues."
While doctors were able to removed the cancerous tissue through multiple surgeries over the course of two years, Smulders admits she doesn’t know if she’ll ever feel "cancer-free."
"Now that I'm five years out, I'm trying to think of it as a positive thing and what can I learn from it," she says. "And if I can create more awareness, I'll do it."
Read more about Cobie’s story in the May 2015 issue of Women’s Health, on newsstands now.