Linda Hamilton Linda Hamilton

Days after her first appearance on Chuck, Linda Hamilton is on the set of the NBC spy comedy working hard. She's shooting an important scene that requires multiple takes of her running back and forth, and back and forth. "For such a light-hearted romp, they sure do shoot a lot," she tells reporters on set. "There's like two hours' worth of action in every hour. We are spending our good long days working hard to make it all look easy."

Chuck producers: Chuck has mommy issues

If there is anyone who can make the action look easy, it's Hamilton. More than two decades after her breakthrough role as Sarah Connor in Terminator, the 54-year-old actress has signed on to play Mary Bartowski, Chuck's mom. Coupled with her appearance on Weeds as Nancy Botwin's hippie pot supplier, Hamilton is having fun showing her more comedic side. "That's the reason I really wanted to do it. Because the other stuff I've done once or twice," she says. "It has such a light touch, when I watched the show, I actually laughed out loud a few times. I love the fact that it doesn't take itself too seriously."

Watch full episodes of Chuck

After Chuck's father (Scott Bakula) died in the Season 3 finale, he left behind an audio file about a secret organization with which Chuck's long-lost mother (and a former spy) also worked. Hamilton was a fan favorite to step into the role and executive producers announced the sci-fi dream casting at Comic-Con to thousands of Chuck's biggest fans.

"And I still know almost nothing. It's the most vague kind of acting," she says of the role. "I went into work the first day and did three scenes where I'm shooting people. I'm like, 'Am I the good girl?' [The writers] are like, 'Hmm, we don't know.'"

Linda Hamilton to play Chuck's mom — and guess who's pregnant?

Hamilton is signed on for four to seven episodes this season. Although she and Zachary Levi have yet to have any scenes together, she teases that Mary will find her son soon enough. So what will her relationship with Chuck be like? Hamilton says it will be more cold and by-the-books than an emotional reunion. "Forget all the other stuff that's been missing for 20 years," she says of her character's long absence.

However, expect some more motherly scenes for Hamilton alongside her on-screen daughter, Ellie (Sarah Lancaster). "It's a whole different animal," she says. "To just be able to have feelings that are underlying come forth a bit, as opposed to just stuffing it all down and being the professional, it's a wonderful opportunity."

Hamilton has no idea how long her guest stint on Chuck will last. "They always warn you, we kill our actors now," she says of the writers. But she's enjoying the ride nonetheless.

"It's glamorous. It's fun. Its back to the TV I did in the '80s. I mean, the clothes are better," she jokes.

Chuck airs Monday at 8/7c on NBC.