Pedro Andrade / Pacific Coast News 1 / 6
Pedro Andrade / Pacific Coast News 1 / 6

While promoting her new action-comedy "Killers," co-starring Ashton Kutcher and Tom Selleck and in theaters June 4, Katherine Heigl admitted to ET's Samantha Harris that she regrets leaving "Grey's Anatomy" every day, but said she's grateful that she chose to raise her baby daughter Naleigh full-time instead.

"It was a really hard choice to make and you never quite know, 'Was it the right choice or the wrong choice?'" Heigl said of leaving "Grey's." "But the only thing that gives me solace is knowing that if I hadn't [left], I wouldn't have had these months with Naleigh that have just sort of solidified our relationship."

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"I needed that to happen," she continued. "I really needed her to get that I'm her mom. And I needed to show her that, I couldn't just tell her."

Heigl, who adopted Naleigh from Korea last September with her husband Josh Kelley, told ET she hasn't seen the "Grey's" season finale yet, but she plans to catch it soon on i-Tunes -- and she confessed that she can't help but wonder how her character Izzy's tale would have played out.

"As much as I miss my friends [on the show] and wonder what Izzy's storyline would have been in the season finale, I am so, so grateful that I chose to give [Naleigh] this time. She and I needed it."

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"She's just getting more and more fun every day, like the walking, the talking and mimicking," added the proud mom. "She's super-goofy and has a great sense of humor which is just awesome for us, because we love to laugh.

"It's been really amazing to have that time with her, for sure, and to be just Mom, and be involved and be in charge," Katherine said. "And so now it's hard to go back to work, but there is a big part of me that's anxious to go back to work."

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Catch the full interview on Monday's Entertainment Tonight.

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