Katherine Heigl reportedly 'wanted out' of 'Grey's Anatomy' because it was 'so hard' working with Shonda Rhimes, according to a new book

• Katherine Heigl reportedly found it "so hard" to work with Shonda Rhimes on "Grey's Anatomy."
• An anonymous source spoke to Lynette Rice for a new tell-all book about life on set of the drama.
• Heigl said she "ambushed" writers when she infamously withdrew her name from Emmys consideration.

Former "Grey's Anatomy" star Katherine Heigl developed a reputation for being "difficult" in Hollywood after her infamous 2010 exit from ABC's hit medical drama, as Entertainment Weekly's editor at large Lynette Rice recounts in "How to Save a Life: The Inside Story of Grey's Anatomy," But according to the tell-all book, there was more to the story behind her departure.

Rice spoke to several sources who chose to remain anonymous for "How to Save a Life." One "person familiar with the situation" suggested that Rhimes shares some blame in the matter of Heigl's exit. According to that source, the "big issue" was that Rhimes "felt like the star of the show and resented that the actors were becoming stars of their own."

While it was suggested at the time that Heigl had departed the hit show because she wanted to pursue a career in movies, Rice's source said that wasn't exactly the case. "It had nothing to do with her film career," the source told Rice. "She wanted out because it was so hard working with Shonda."

The source said that while Heigl wasn't always the easiest person to deal with on set, they feel like "Katie got a raw deal" in how the situation played out publicly.

A separate anonymous source, identified by Rice as a former ABC Studios executive, added that "there could have been a happy medium" where Heigl could've pursued a film career and kept "going for six to eight episodes [a year]" on "Grey's Anatomy." But ultimately, the show couldn't find "a great way to compromise the work schedule that didn't negative affect the crew or the cast," as Heigl put it in a post-exit interview with Entertainment Weekly, according to the book.

"I think Steve McPherson and Shonda were just so fed up with it all, they just said, 'Get her out,'" the former studio exec said, per Rice.

Representatives for Rhimes and Heigl didn't immediately respond to Insider's request for comment.

Heigl has expressed regret for some of the public drama between herself and the 'Grey's Anatomy' writers

Before her exit, Heigl drew headlines for her extremely candid comments about the quality of her storylines on the show.

In 2008 - after she had already won an Emmy for her role as Dr. Izzie Stevens the previous year - Heigl told Entertainment Weekly in a statement that she withdrew her name from Emmy consideration because she "did not feel I was given the material" worthy of one of the highest awards in television during that year's period of eligibility. She also said she wanted to "maintain the integrity of the academy organization."

"How to Save a Life" recounts Heigl's regret over that incident, which was perceived as a slight against Rhimes. According to the book, she told Entertainment Weekly in 2010 that she "could have handled the situation more gracefully" and privately addressed the matter with the "Grey's" writers without causing an "ambush."

Heigl had also spoken out about the work conditions on the "Grey's Anatomy" set in a 2009 appearance on "The Late Show with David Letterman," calling the length of her work day "cruel and mean" and specifically saying she was speaking out in the hopes of "embarrassing" the powers that be on the show.

According to the book, Heigl also told Entertainment Weekly in 2010 that in retrospect, she was "embarrassed" by how "whiny I sounded" during the Letterman appearance.

"How to Save a Life: The Inside Story of Grey's Anatomy," out now, gives readers new details about life on the set of the mega-hit drama.