The 54-year-old singer enrolled on a four-day masterclass in June with acclaimed acting coach Bernard Hiller, reported Daily Mirror.
"In June, I went to a course run by a fantastic man called Bernard Hiller. He was brilliant. It was a masterclass in acting that was based in London for four days.
"He's worked with some of the best people in Hollywood and he taught us how to resolve performance nerves and self discovery as well as inside-outside acting and how to be public with private emotions. It was brilliant and it's really helped with my performance on stage as well."
"I think it would be fun to have me in the various crowd scenes - almost like a Where's Wally? See how many times you can spot the real Susan in the film!
"In all seriousness, I'm very excited about this project. The script is great and the team behind it are brilliant.