12/10/2012 10:32 am ET

Megan Fox's Baby Noah Changed Her Life: 'I Love Him So Much It Hurts'

Everyone told her what to expect, but Megan Fox admits she didn't grasp the concept of motherhood until welcoming her son, Noah Shannon, in September.

The "This Is 40" star, 26, gushed about her 2-month-old baby boy at the March of Dimes Celebration of Babies event on Dec. 7.

"The whole thing has been overwhelming because I didn't realize you could love something so much," Fox told E! News, continuing, "and I know people always say that, but I love him so much it hurts, and it's an interesting feeling to have because I never felt that before."

Fox, who is also stepmom to husband Brian Austin Green's 10-year-old son Kassius, recently revealed that she's looking at her career differently now that she's a mom.

"It changes your perspective about being overly sexual in a film when you have a baby," she told the Mirror. “I’m going to be more cautious about choosing films because I’m already thinking about when he’s in school and his friends are going to be showing him my photo shoots with me in a bikini and he’s going to be horrified."

But for now, all that's on Fox's mind is her new bundle of joy -- and all the milestones that are yet to come.

"He's getting to that place where he's smiling and he's almost ready to laugh, and I can't wait for that baby laugh that almost makes you feel like you can fly," Fox gushed to E!, "like your heart's going to explode."

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