Don't let her famous family tree fool you. The star of ''Martha Marcy May Marlene'' — and sister of moguls Mary-Kate and Ashley Olsen — is kick-starting her Hollywood career the old-fashioned way: by delivering a star-making performance

By Sara Vilkomerson
October 07, 2011 at 04:00 AM EDT

When the psychological thriller Martha Marcy May Marlene became a festival darling at Sundance last January, much of the chatter focused on its leading lady, Elizabeth Olsen. And with good reason: The 22-year-old actress — younger sister to the Olsen twins of Full House fame — is riveting in her debut film role, playing a mysterious young woman adjusting to life outside of a (way creepy) cult. ”It’s cool and exciting, but it’s also very weird,” says Olsen of being the sudden object of an industry and media crush. The downside? ”Now there are high expectations,” she explains. ”[Other actors] are able to get away with things at the beginning of their careers when they’re still learning, because their movies tend not to be seen. I’m still figuring it out.”

She’ll have to keep learning on the job. Olsen is due to have a very busy 2012, with at least three films slated for release: Red Lights, a thriller costarring Robert De Niro and Sigourney Weaver; Liberal Arts with Zac Efron, Allison Janney, and Josh Radnor; and Very Good Girls, about two high school best friends, costarring Dakota Fanning.

Good thing multi-tasking runs in the family. Olsen says her clan is greatly supportive, from her entrepreneurial sisters to her parents. They’ll gather for Martha Marcy May Marlene‘s NYC premiere to see the movie for the first time — though her father already saw it in Toronto, with Elizabeth covering his eyes during risqué scenes. But the actress recognizes that there are both pros and cons to following her older sisters’ career path. ”It scared me a bit in high school because I thought, ‘If I go into this professionally, will I get a lot of crap from people thinking that the only reason I get a job is because of this and that?”’ says Olsen. ”Then I started working, and it gave me the confidence to earn my own place.”

Her famous siblings certainly weren’t a factor when Olsen first auditioned for Martha Marcy May Marlene. ”Lizzie stood out immediately,” says writer-director Sean Durkin, who was informed about Olsen’s lineage only five minutes before meeting her. ”She had a strength in her presence and an extra level of depth without trying. She’s very focused but effortless as well. She really works like a much more experienced actor.”

For now, Hollywood will have to compete for Olsen’s attention. She’s also getting a degree in theater from NYU’s Tisch School (Olsen left the Toronto Film Festival before the premiere of another of her films, Peace, Love & Misunderstanding, in order to make the first day of classes). ”I love school and want to finish,” she says. ”I keep telling myself: This won’t be the only time you’ll get to work!” Trust us, it won’t.