Lupita Nyong'o Reveals Why She Felt 'Panicked' While Making 'Us' (Exclusive)

The Oscar winner opened up to ET about why she almost backed out of starring in Jordan Peele's latest horror film.

Lupita Nyong'o is an Oscar winner and one of Hollywood's most sought-after and celebrated actresses -- but even for her, the daunting prospect of playing two rival characters in the same film got under her skin.

ET's Nischelle Turner spoke with the 36-year-old actress on Tuesday as she was promoting her upcoming horror film, Us, and she opened up about working with director Jordan Peele, and why she almost backed out of playing the lead role

"Whenever I start a film, I am my worst enemy for sure, and this film was no different," Nyong'o explained. "For a second there, I really was worried for myself that I would give up and buckle and just be like, 'Jordan, I think you need to find another actor, because I just don't have what it takes.'"

In the film, Nyong'o plays Adelaide, a wife and mother whose family finds themselves trapped and terrorized by a group of murderous doppelgangers, whose very existence leads down a twisted rabbit hole of mystery and terror.

"I was playing not one, but two characters in the same movie and I was panicked, because usually I have the time it takes to prepare for one film and [even then], the critic in my head is powerful, and she knows how to freak me out," Nyong'o added. "It took having people I love around me who could remind me of the things I wasn't able to see for myself, and to build that confidence."

Despite her trepidation, the actress said that one of the things that most attracted her to the frightening project was the chance to work with Peele, whose directorial debut, Get Out, has become an instant thriller classic and was nominated for four Oscars, including Best Picture. Peele himself took home one of the coveted golden statues for penning the film's screenplay.

"He was someone I admired from Key & Peele, and working with him was [on my] bucket list," Nyong'o explained. "He's so talented, so funny, so cool, and I was like, 'Oh, I would kill to work with him!"

"Then, a few months later, he's like, 'Here's a script and you get to work with me twice,'" she recalled, referring to the fact that she played two completely different characters in the film. "And I was like, 'Ahh!'"

While she got the chance to work with Peele for the first time in Us, the movie served as an opportunity for Nyong'o to reunite with her Black Panther co-star Winston Duke, who plays her husband this time around.

"To have Winston as my scene partner was such a comfort, because we went to the same school -- we speak the same dramatic language because of that -- and we have Black Panther behind us," she shared. "So we have a friendship, we have an intimacy that is unbreakable."

"I could trust him and go to dangerous places and I knew he was there to really support my process and I could support his," she added.

Peele's hotly anticipated Us -- which also stars Shahadi Wright Joseph, Evan Alex, Elisabeth Moss, and Tim Heidecker -- hits theaters March 22.