The actress, who has recorded two albums, has never sung on film before and she admits it was a dream come true to combine her two passions.
She says, "Apart from singing the title track on the Phantom of The Opera soundtrack this is my first time singing on film. It's the best experience I've had.
"It was incredible singing all the music from the 70s; I sang a Beach Boys song, I sang a Dusty Springfield song. My favourite was singing Strange Magic. The orchestra in the movie were these kids from seven to 17 and they had been workshopping for the last three years.
"They played everything on all of the tracks. So you have Life On Mars by David Bowie played by these kids incredibly."