Katherine Heigl was a fan favourite on “Grey’s Anatomy”, yet her exit from the beloved medical drama was clouded with controversy.

That scandalous chapter in “Grey’s” history is detailed in new excerpt from Lynette Rice’s How To Save A Life: The Inside Story Of Grey’s Anatomy, published in theDaily Telegraph.

In the excerpt, Heigl attempts to set the record straight to reveal the real motivations underlying her decision to leave.

Speaking of her controversial exit, Heigl revealed that a confluence of things led to her decision to leave, starting when she learned the network was planning to offer salary increases to co-stars Ellen Pompeo, Patrick Dempsey, Sandra Oh and Isaiah Washington, leading her to publicly declare she wasn’t going to be renegotiating her contract.

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“In this town, women who don’t just snap and say, ‘Okay, yessir, yes, ma’am’ start to get a reputation for being difficult. I’ve decided it’s not worth it to me to be pushed around so much,” she explained.

Things came to a head when Heigl was perceived as taking a shot at Rhimes and the show’s writers when she withdrew herself from Emmy consideration. “I did not feel that I was given the material this season to warrant an Emmy nomination and in an effort to maintain the integrity of the academy organization, I withdrew my name from contention,” she said in a scorched-earth statement.

Looking back, Heigl admits she didn’t think it was a big deal at the time, but has come to see why her statement elicited the controversy it did.

“I thought I was doing the right thing. And I wanted to be clear that I wasn’t snubbing the Emmys,” she said. “The night I won was the highlight of my career. I just was afraid that if I said, ‘No comment,’ it was going to come off like I couldn’t be bothered [to enter the race]. I could have more gracefully said that without going into a private work matter. It was between me and the writers. I ambushed them, and it wasn’t very nice or fair.”

However, Heigl is adamant that the key reason underlying her exit was that she had recently become a first-time mother. “I started a family, and it changed everything,” she said. “It changed my desire to work full-time. I went on family leave and just got to be a [mom], and it changed my whole perspective… that was really the turning point. So before I was due back, I spoke again to Shonda about wanting to leave. Then I waited at home until I was given the formal okay that I was off the show. The rumours that I refused to return were totally untrue.”

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According to Heigl, both she and Rhimes worked to find a solution that would work for both the actress and the show, but were unable to do so.

“[Shonda] wanted to try to figure out how I could do both [parenting and ‘Grey’s’], and I kind of wanted to do both. There wasn’t a great way to compromise the work schedule that didn’t negatively affect the crew or the cast. It wasn’t feeling fair to them or the show to ask them to bend around my needs,” Heigl explained.

Meanwhile, two anonymous sources share differing accounts of what took place. According to a former ABC exec, both Rhimes and Steve McPherson — then president of the network — had become “so fed up with it all, they just said, ‘Get her out.'”

However, another insider pointed out, “There were two sides to that story. Katie was just beaten up for having an opinion, for being successful, for not kissing the ring. She became much bigger than Patrick Dempsey, but she didn’t have a penis.”

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When it was all said and done, Heigl admits she bears some blame for the negative public perception that followed her exit. “The ‘ungrateful’ thing bothers me the most. And that is my fault,” she said. “I allowed myself to be perceived that way. So much about living life, to me, is about humility and gratitude. And I’ve tried very hard to have those qualities and be that person, and I’m just so disappointed in myself that I allowed it to slip. Of course I’m grateful. How can I not be?”

How To Save A Life: The Inside Story Of Grey’s Anatomy will be released on Sept. 28.