Phyllis Somerville, 66, knew she wanted to be an actress when she still barely knew how to walk. But despite a lifetime of film and TV appearances, as well as stints on Broadway, the past few years have been an especially breakout time for the Iowa native. Besides appearing in the Best Picture-nominated The Curious Case of Benjamin Button, Somerville earned raves as the mother of the child molester played by the also-nominated Jackie Earle Haley in Little Children.

Now, Somerville has a weekly outlet for her talent. On Showtime’s The Big C, which airs Monday’s at 10:30 p.m., Somerville plays Marlene, a woman who had shut out the world but finds a new lease on life from her relationship with Laura Linney’s Cathy Jamison, who’s facing cancer in an unusually optimistic fashion.

Somerville spoke to AARP about Marlene, Little Children and being an older actress in the Betty White era.

Q: When you first saw the script for The Big C, what did you think about the show’s approach to cancer?

A: I like humor that’s dark. Having had people in my family die, there was never a moment at any of the funerals where we didn’t get into some kind of giggle fit. When your emotions are that close to the edge, there has to be laughter. I think that’s really good theater, and I think these scripts do that very well.

Q: Talk about how you approached Marlene, a woman who, at first, hides from the world.

A: We all know times when we would rather just hide under the couch. One of the things I liked in the pilot is that in their first encounter, Marlene and Cathy both saw somebody who is going to answer back. She comes in, she yells at me, I yell back, she yells back again, and I’m certain that Marlene sat there and said, “Huh. I gotta talk to this lady again.”

Q: Do you call on thoughts about people in your life to help you prepare for roles?

A: I’m not a method actress. I tend to call upon myself. Emotionally, I’ve watched other people respond to things. But for physical things, I’ve seen an interesting walk and then, hoping not to get caught, follow and copy that walk down the street. The physical things — the way somebody talks or walks, or their gestures — I’ll steal that. I steal from people on the street, I steal from my friends and I steal from really good actors. I always know when I’m really liking a performance, because I sit there thinking, “I’m gonna rob you blind.”

Q: You’re the daughter of a Methodist minister. Were there elements of being a minister’s daughter that helped prepare you for an actor’s life?

A: If you’re a Methodist minister’s daughter, until you get to the big church — which my dad never did — they move you around a lot. So I was a little bit of a gypsy as a kid. Also, my father had a great sense of theater in the pulpit. Not an evangelical fervor; he just knew how to get focus. And he took me to a lot of movies. He took me to [Laurence] Olivier’s Hamlet when I was 4.

I’m from Iowa, so there wasn’t a lot of professional theater around, but there were colleges, so he would take me there. Before I was 10, I saw Pygmalion, Romeo and Juliet, The Merchant of Venice. He took me to see Marian Anderson in a small college in Iowa in the ’50s.