Katherine Heigl Leaving 'Grey's Anatomy'?

Hollywood, CA (BANG) - Katherine Heigl is considering leaving hit TV show 'Grey's Anatomy' to concentrate on her film career, it has been claimed.

The 29-year-old actress - who has found success in romantic comedies 'Knocked Up' and '27 Dresses' - is said to be keen to end her contract with the medical drama to focus entirely on movies.

A source close to the actress said: "She's working really long hours and is ready to move on. She's a smart one. "

"She saw what can happen with someone like Jennifer Aniston, who was crazy successful on TV, but can't seem to carry a film, and she tested the waters early."

However, Katherine - who made headlines when negotiations for her contract renewal on the show were made public 15 months ago - may be locked into her contract and will have to continue starring as Dr. Isobel Stevens.

The source added to Us Weekly magazine: "I don't think she'll be able to get out of it."

Katherine can next be seen in romantic comedy 'The Ugly Truth' with Gerard Butler. Since starring as Rachel Green in 'Friends', Jennifer has appeared in a host of films, including 'The Break-Up' and 'Bruce Almighty', but has failed to shake off her TV character.