ABC News' Karen Leo reports:

Lupita Nyong'o is Hollywood's new "It" girl.

Born in Mexico and raised in Kenya, the actress is taking the entertainment and fashion industries by storm. It's an impressive achievement, considering that her Oscar-nominated performance in the acclaimed film "12 Years a Slave" is her first big movie role since she earned a master of fine arts from the Yale School of Drama in 2012.

In an interview with "Good Morning America" co-host Robin Roberts, the 30-year-old talked about playing the role of Patsey, the spirited slave who was brutally abused by her master, played by Michael Fassbender.

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"I remember in my first rehearsal with Michael, he was like, 'How are you doing?' and I said, 'I'm really nervous.' And he said to me, 'So am I.' And that was so good to hear," she said.

She described the first time she realized the impact that the film - and her performance - had on viewers.

"Well, yeah, it was, very early and there was a couple, an older couple that had just come from the film. The older gentleman, he could barely speak but all he said was, 'Thank you,'" she said. "And he reached out for an embrace and I held him, and he was just - broken. And, yeah, that was the first time I realized, 'Wow, this is - this is bigger than all of us.'"

The film's director, Steve McQueen, auditioned more than 1,000 actresses for the role of Patsey.

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There are high expectations for Nyong'o's future, but she's not letting the pressure get to her. Focusing on that would only "cripple" her, she said.

"So you're not as concerned about what's next?" Roberts asked.

"I'm not concerned," Nyong'o replied, laughing. "I'm curious, I'm excited, I'm ready."

As for how ready she'll be for the red carpet at the Academy Awards on Sunday, Nyongo - who has turned heads for her sense of style - wasn't giving any hints about what she would wear.

"Mum's the word," she said.