Ethan Slater played both Glinda and Nessarose in his 'Wicked' audition tape

He told People magazine's special Wicked issue: "I did two scenes and sang Boq's songs, 'The Ozdust Ballroom' and 'March of the Witch Hunters,' which is the second movie.

"But, I should say that I didn't have anyone to read with at the time, so the tape I sent in is me playing Glinda and Nessa off camera, and then me reading with a video of myself."

Ethan admitted the move was "so bold" but he ultimately felt it was the right thing to do.

He added: "I can't believe I got away with it. But I knew I wanted to take my time with it ... and I couldn't get somebody to spend that time with me, so I just did it with myself."

Ethan is dating Ariana Grande, who plays Glinda in the film, and he hailed her "masterful grip" on the comedy of the role.

He gushed: "One of the things that was really fun to see is, she has a masterful grip on comedy, and she's so funny and so physical, and it never feels like a joke on top of the character. It always feels like it's coming right from Glinda. You get lost in the performance - she just is Glinda. Even in those incredibly funny physical moments."

The cast also includes the likes of Cynthia Erivo, Jonathan Bailey, Jeff Goldblum, Peter Dinklage and Marissa Bode, and Ethan praised all his co-stars for their commitment to the project and their characters.

He said: "The thing that felt really special is how much everyone cared about their characters.

"When you're working on something that's been around the world for 20 years and these are characters that the fans love and care about, it's really important that the actors portraying them in a movie of this scale care as much as everyone else. And everyone did."