Daryl Hannah's sweet shyness in films like "Splash" and "Steel Magnolias" wasn't just an act.

The 52-year-old has revealed a secret struggle with autism, which she was diagnosed with as a child, and says she has spent her entire life battling a "debilitating shyness" as a result of the disorder.

The actress, who has appeared in more than 50 movies (also including the "Kill Bill" series, "Blade Runner," and "Wall Street") and has had high-profile relationships (John F. Kennedy Jr. and musician Jackson Browne are exes), told People magazine that growing up in Chicago, she exhibited many of the signs of autism: She was disconnected from other people. She would — and sometimes still does — incessantly rock her body. And when it came to school, she "checked out."

Doctors diagnosed her with the disorder at a time when it was not at all understood. Their recommendation? That she be medicated and institutionalized. However, her mother, Susan, who was a teacher, wouldn't allow that to happen. Hannah said she found comfort watching old movies, and when she was 17, she moved to Los Angeles to pursue a film career.

The famous blonde quickly shot to stardom, but because she is a "socially awkward, incredibly shy person," she developed a reputation as a diva when she refused to meet with movie execs, appear on talk shows, or attend her own premieres. (According to reports, she once fainted on the set of "Late Show With David Letterman," and had to be medicated to attend the Academy Awards.) It was "not because I was above it, but because I was terrified," Hannah said.

"I've seen her so nervous she's literally shaking on a red carpet," her best friend, Hilary Shepard, told the magazine.

Hannah said she's enjoying life more now that she's in the spotlight less. While she still occasionally appears in movies, she focuses on her environmental activism (she was arrested earlier this year outside the White House with Robert Kennedy Jr. and his son Conor) and lives off the grid on a ranch filled with animals (a one-eyed dog and rescue pig included) in Los Angeles.

No doubt, Hannah — who denies to People that she's ever had plastic surgery — is enjoying life more now that she can open up about her autism diagnosis. Previously, she's spoken about her crippling shyness and social difficulties as a child but made only vague references to the disorder. One was to in an interview with the environmental group Amazon Watch in 2007, in which she said, "I maybe had Asperger's [syndrome, an autism spectrum disorder]. It wasn't widely understood at the time."

"I'm a grow-up now," Hannah, who has been linked to Wallflowers keyboardist Rami Jaffee, told People. "I've learned a couple of things that would have really made my life easier if I'd only known them 20 years ago. … I wasted so much time scared, self-conscious, and insecure."

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