Brooke Shields says she ran 'butt naked' from college boyfriend Dean Cain's college dorm room after losing her virginity at 22

• Brooke Shields has spoken about her surprising reaction when she had sex for the first time.
• In "Pretty Baby: Brooke Shields," the actor said she lost her virginity to Dean Cain when she was 22.
• "I feel bad for that girl. She was old enough to own her own body," she said about her younger self.

Brooke Shields has recalled her surprisingly intense reaction to having sex for the first time.

Speaking in her new two-part documentary, "Pretty Baby: Brooke Shields," which is now streaming on Hulu, the model and actor opened up about losing her virginity at the age of 22 to her college boyfriend, Dean Cain.

Cain, who went on to star as Superman in the TV series "Lois & Clark: The New Adventures of Superman," dated the "Endless Love" actor when they were both undergraduates at Princeton University. 

While Shields had been previously romantically linked to the likes of Michael Jackson, John Travolta, and John Kennedy, she said in the documentary that Cain was actually her first real boyfriend.

"I wanted to jump into the personal relationship and the love and the commitment," she said to camera in the documentary. "The part he was more comfortable with was the sexual part and I wasn't, so we had to teach each other about the other."

However, on the night that they decided to have intercourse for the first time, Shields said that thanks to her previous public admission that she was a virgin, "the stakes were so unnaturally high."

In 1985, when she was 20 years old, Shields penned a coming-of-age manual for college-age girls titled "On Your Own," in which she confirmed that she was practicing abstinence — something she immediately began to be grilled about in interviews.

"When we finally had sex, I immediately ran out of the room, down the hall, butt naked, just running. I didn't know where I was going," she said laughing at herself. "He ran after me with the duvet and grabbed a hold of me."

Shields said he calmed her down by reassuring her that she was the same person as she was before and that nothing had changed.

"He got it instantly and I just cried," she said of Cain, who she split from before her college years were over.

Reflecting on her odd outburst, Shields said: "I feel bad for that girl. She was old enough to own her own body, for real. And I just couldn't get there at that moment."

Shields added: "What it boils down to is a sort of a regret for lost exploration and opportunity to understand my personal sexuality."

Shields said elsewhere in the documentary that she had been raised with the belief that she needed to wait until marriage to have sex, even though she had been sexualized from a very young age.

In Louis Malle's infamous 1978 film "Pretty Baby," from which the two-part documentary borrows its title, Shields played a child prostitute, a role that required her to appear naked on camera twice.

She followed this up with two more films that required nude scenes: "The Blue Lagoon," which she shot when she was 14, and "Endless Love," which she shot when she was 15.