Michelle Yeoh had never heard of Wicked

Michelle Yeoh had never heard of 'Wicked' before she was asked to join the cast of the movie-musical.

The Oscar-winning actress plays Madame Morrible in the new film version of the hit stage show - which is based around characters first seen on screen in 1939 movie 'The Wizard of Oz' - but she's confessed she knew nothing about the popular musical before she was approached by director Jon M. Chu about joining the cast.

According to The Hollywood Reporter, she said: "At that point had no clue what he was talking about because I had not seen 'Wicked' the musical before. I knew 'Wizard of Oz', who doesn’t, but not 'Wicked' because I hadn’t been going to the theatres and not doing what I love which is watching musicals, for quite a while I hate to say."

The new movie stars Cynthia Erivo as Elphaba and Ariana Grande as Glinda during their time at Shiz University in the Land of Oz with Michelle's character Madame Morrible serving as the school's headmistress.

Michelle went on to say: "So I read it [the script] and called Jon back and said, 'This is a musical and she sings'. And he said, 'Oh easy, you’ll have fun, you’re up for the challenge'.

"And then the next thing I knew I get this video call and it was him with Ariana and Cynthia saying, 'It’s imperative you come and join us now'."

However, Michelle was scared about singing onscreen for the first time. She explained: "I was terrified, I was not just nervous ... The process of exercising, learning to use the muscles in a different way, was actually very, very good for me because it helps with my voice as an actor. So I had fun."

The movie has been filmed in two parts and the first hits cinemas on November 22.