Brooke Shields' daughter says she only found out her mom had been sexually assaulted while watching her tell-all documentary

• Brooke Shields' daughter said she found out about her mother's alleged sexual assault while watching her documentary.
• "I was learning about things the same time that the world was," Grier Henchy told People.
• Shields said she was sexually assaulted by an unnamed Hollywood executive when she was in her early 20s.

Brooke Shields' younger daughter said she found out about her mother's alleged sexual assault when she was watching last year's eye-opening documentary "Pretty Baby."

Grier Henchy, the model and actor's second daughter with her husband Chris Henchy, told People that she couldn't "get through" the whole documentary after watching her mom emotionally recount the experience on camera.

"I was learning about things the same time that the world was and I just took it more deeply and personally," Grier said.

In the documentary, Shields lifted the lid on her experience of being sexualized from a young age following her breakout performance playing a child prostitute at age 11.

The documentary used a mixture of archival footage and sit-down interviews with Shields, who said for the first time publicly that she had been sexually assaulted by an unnamed male Hollywood executive when she was in her early 20s.

While Shields' other daughter, Rowan, 21, knew about the sexual assault before the documentary's release, Grier, 18, hadn't been told.

"I didn't prepare her," the 59-year-old told People, adding that it was "a miscommunication."

"I had explained it was an exploration of sexualization of women in my industry but I was naively thinking that because we had such a solid, healthy, fairly normal existence and I'm not completely damaged that she would say, 'Wow you've come through a lot but look where we are today,'" she added.

Shields said she tried to tell Grier that there was a "happy ending" but said her daughter responded: "I will never be OK with thinking something bad happened to you."

"She ended up missing the happy part," Shields continued. "She felt helpless, and just as a mom, we make mistakes and sometimes we make assumptions."

In the documentary, which was directed by Lana Wilson, Shields said the assault occurred shortly after she graduated from Princeton University and after she agreed to go for a dinner that she believed was a work meeting.

Afterward, the unnamed attacker invited her up to his hotel room to call a cab and assaulted her once they were alone, she said.

In an interview with The Hollywood Reporter last year, Shields said she didn't know if she'd ever be able to speak publicly about the incident.

"It has taken me many years of therapy to even be able to talk about it. I definitely have worked very hard through it, and I've learned to process it," she said.