Another new report claims that Katherine Heigl is ready to quit US TV show Grey’s Anatomy.

The actress has played Dr. Isobel 'Izzie' Stevens since the medical drama hit TV screens in 2005.

But rumblings that Heigl is keen to concentrate on movie stardom full time following her big screen success with Knocked Up and 27 Dresses refuse to go away.

“She's working really long hours and is ready to move on,” a source close to the actress told Us Weekly. 

A movie industry source adds, “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.”

Just last month, Heigl insisted she had no plans to ditch the show that made her name.

However, it could be that right now she has no choice but to stay.

"I don't think she'll be able to get out of it,” the insider tells Us, referring to Heigl’s contract.