Cynthia Erivo hopes that Prima Facie will lead to a discussion about "how not to consent."

The Emmy, Tony and two-time Grammy winner also spoke at the London Film Festival about the one question her "Wicked" co-star Michelle Yeoh keeps asking her.

Cynthia Erivo knows when to say "yes" and "no" to roles, and hopes her new film will spark discussions about how the word "no" is received in human relationships and society.

That was one of the highlights of the star's packed talk on Monday during the 70th BFI London Film Festival (LFF), which runs until October 18.

In a wide-ranging conversation, the Emmy, Tony and two-time Grammy winner and three-time Academy Award nominee discussed her career, including her latest film, Prima Facie, in which she plays a lawyer who becomes a rape victim. Erivo previously told THR that working on the film made him "feel sick and angry."

'Beatles' movie release details: A big month of filmmaking, producers hope

Ava DuVernay Says 'The 14th' Saved Her and 'Hollywood Is Over'

The star hopes the film can help start a discussion about "preconceived notions of how black women experience pain" and more general consent, along with how to hear and accept "no" in a broader sense. "We expect to feel more violence for him. We expect him to be in more pain than what we see," Erivo shared. "And I hope that when people watch this film, they will realize that this is an act of violence."

She also said, "Consent is hard for all of us to understand sometimes. It's a big complicated thing that has more to do with how we receive 'no' than how we see 'yes.'

During his appearance, Erivo also praised his co-star and co-ordinator Daniel Ings. He said of Ings that he was very, very kind from the beginning and immediately wanted to talk about how we could protect each other and how we could help in those places, in those moments, so that we could go as far as we needed to go and then come back again.

And she argued, “I think intimacy coordinators are not given enough credit. They often have a hard time with what they have to do on set. "But what they do is really important, and it's not just about designing a scene, a sex scene, a love scene, a love scene — but sometimes you have to not only design these really tough, heartbreaking scenes, but also make sure that everybody gets back safely."

On Monday, Erivo also mentioned regularly sharing a "no" when offered roles, insisting, "I feel like I have an internal metronome that tells me when something is right for me and when something isn't." As a result, the actor explained, "I say no to a lot of things."

Of portraying real people, she said, "I play these women who have given birth to amazing things, probably because I care about them. These women deeply, and I want the world to see them as they were — with all their complexity and greatness, and some of their failures, because they're human. "I guess what I love about these women is the deep humanity that each of them has."

When Erivo was approached about Prima Facie, the star recalls, "I knew immediately that I wanted to do it because I knew how important it was." "I also had the feeling that it was more important than I was even aware of and I wanted to be a part of it."

With his production company, he seeks to tell complex stories with complex characters, including vehicles for great young actors. For example, Erivo pointed out; that he wants to find something interesting for Demi Singleton.

Asked about her mentors, she shared that Michelle Yeoh is one of the big stars who call her and "look for me." Erivo even recalled to laughter from the audience that Yeo had asked him between scenes of Wicked when he would direct for the first time. And she shared, "He asks me questions every time I see him."