March 18 (UPI) -- Rachel Zegler says filming the live-action Snow White remake was "the hardest thing" she's ever done.
The 23-year-old actress and singer discussed the film during Monday's episode of Jimmy Kimmel Live! She also performed "Waiting on a Wish," which is featured on the film's soundtrack that dropped Friday.
She wore a red and white dress with a red bow in her hair during her performance.
"Feeling trapped in the walls that hold her, feeling stuck in a story they've told her," she sang. "Another day where she fades away, never daring to disobey, so she's dreaming all alone, sharing secrets with a stone."
Prior to her song, she discussed the role with Kimmel.
He asked her if it was challenging to shoot a film that blended live action with animation.
"It's the hardest thing I've ever done. It's amazingly rewarding when you see it and when you complete it to say that this a thing that we did, but you basically do three different versions of every scene," she said.
She said they filmed the first pass with humans, followed by a round with puppets, and then a "clean pass" after that.
"It's essentially me doing 'Whistle While You Work' to nobody..." she explained.
Zegler is well-known for her roles in West Side Story and The Hunger Games: The Ballad of Songbirds & Snakes. She is also set to portray Eva Peron in Evita in London's West End this summer.
Snow White arrives in theaters Friday.
