"Whenever you get to do a really good movie or a really good job (like theater), ... it's like you're in camp," she says. "You're going on an adventure and you're just so stimulated."
And the Manhattan Theatre Club production definitely is stimulating.
Written by Donald Margulies, the play opened last month to excellent reviews and has been extended through March 27. It concerns a war photographer named Sarah (Laura Linney) and her journalist boyfriend (Brian d'Arcy James).
Sarah returns home to New York after being injured in Iraq. She's readjusting to life away from the front lines of battle and reconnects with her editor (Eric Bogosian) and his much younger girlfriend Mandy (Silverstone), who provides much of the play's comic relief.
Upon meeting Sarah for the first time, Mandy brings two balloons. One balloon says "Welcome Home" and the other, "Get Well." Mandy earnestly, absurdly confesses she couldn't decide which balloon was more appropriate to the situation so she brought both.
"She's really very young and fresh and from a different world," Silverstone explains.
While Sarah, her boyfriend and editor read The Economist and The New York Times, Mandy is more of a follower of Us Weekly and Oprah Winfrey than what's happening in the world on a global scale.
Yet, Mandy's perspective is broader than appears. When she sees photos Sarah took of a dying boy, she cries, asking why Sarah didn't do anything to help. Sarah believes it was her duty to take pictures; Mandy thinks Sarah should have done something in an effort to keep the child alive.
It's that type of engagement that makes Silverstone thrilled to be in the production.
"I didn't want to go to the bathroom in rehearsals because I didn't want to miss anything. I was so excited. It was so stimulating. Just the energy in the room," says Silverstone. "You've got these people who are passionate and inspired and artistic and thoughtful and intelligent and ... there's a pulse in the room."
Director Daniel Sullivan says Silverstone has a zest for life.
"Alicia is a breathe of fresh air," he says. "I think she brings that onto the stage. She's a huge enthusiast for life. That's something she carries with her. ...There's a moment in the play when her character asks the others to feel the joy in the world. I think that's a very personal statement for Alicia. "
This isn't Silverstone's first time on Broadway. She co-starred in "The Graduate" with Jason Biggs and Kathleen Turner in 2002.
Silverstone's career began to take off in the late 1990s as a recurring star of Aerosmith music videos and then in the film "Clueless." She soon was considered one of a Hollywood "It Girl."
Now 32, Silverstone still looks like the high school student she played in "Clueless." She attributes that to a vegan diet and recently wrote the best seller "The Kind Diet" to introduce the lifestyle to others.
"It's like I have a magic, secret toolbox that handles everything and I want everybody to have it because it's amazing," she gushes.
Silverstone says changing her diet has absolutely helped her work, particularly in making the right choices when it comes to picking projects, such as "Time Stands Still," which has been extended through March 27 at the Friedman Theatre.
"It really opens your heart up and takes the gunk away. All that nasty food we put in our body that is just gunking up our system ... it's hard to know what's your right move. So I feel grateful for (my diet) because of the clarity I feel."