LONDON: Hollywood actress Jennifer Aniston is urging critics not to write off her singing abilities as she prepares to belt out tunes in a new movie - because her vocal performance "won't be bad".

The 40-year-old is finding her voice for her first major musical role as the star of The Goree Girls, which chronicles the exploits of a 1940s-era band comprised of all-female prison inmates.

And she insists she'll surprise film fans.

It's a little-known fact that Aniston studied singing as a teen attending New York's High School of the Performing Arts - the inspiration for classic movie musical Fame, and Aniston, who is also learning to play guitar for the film, insists she won't disappoint.

She tells People.com, "I can carry a tune. It won't be bad. Here's the good news: the band - they weren't musicians. They basically created a band in prison in order to get paroled.

"So you're dealing with new singing voices and new instrument playing and somehow they find a way and become a huge phenomenon. It's a true story."