Megan Fox says having a kid won't cramp her social style

At 25, Megan Fox is not only married, she's married to an original “90210” cast member (Brian Austin Green), and she’s also a stepmom to his nine-year-old son, Kassius.

Fox says the mom part is way more challenging than being in a Hollywood relationship.

“Of those three, (parenting) is definitely the most difficult,” she told FOX411. “There is the most reward in it, but there is also the most pressure, guilt and worry.”

Fox also sounded pretty certain that she wants to have a baby of her own, and isn’t worried about any consequent changes to her social life.

“I’ve never really socialized, I’ve always been anti-social and preferred to be at home,” she said. “I was never, even my late teens and early twenties, into clubs and parties and stuff like that. So I feel like the transition will be fairly easy, in that sense, for me.”

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The sexy “Transformers” star flexes acting muscles of a different kind in the newly released romantic comedy, “Friends With Kids,” which centers around two best friends (Jennifer Westfeldt and Adam Scott) who decide to have a child together while keeping their relationship platonic, in an effort to avoid the toll having children can take on romantic relationships. Fox plays a woman who Scott's character falls for post-baby, complicating the situation.

Fox said that on a personal level, she doubts she could ever commit to a friends-only parenting arrangement.

“I feel like if you are with someone through the process of pregnancy and delivery, if nothing else, there is such an incredible amount of respect that would lead into some sort of love in one way or another,” Fox continued. “And it would become confusing in that situation.”

Jon Hamm, who also stars in and produced the movie, concurs.

Long before he hit the Hollywood big-time, a then twenty-something Jon Hamm – who is has been in a relationship with Westfeldt for over a decade – was asked by a pal to procreate.

“I have actually been asked to be a father by a friend who wanted to have a kid. It was kind of weird and out-of-nowhere and I said no,” he told us. “Mainly because I was totally unemployed, and I would feel so responsible, even though they said ‘don’t worry, no strings attached.’”

And now?

“I would totally do it,” Hamm quipped.

For the time being, however, it sounds like Hamm is happy living the kid-free life.

“I love other people’s kids, especially when they are about three to eight years old because they are fun and they speak English,” he added. “Well, I mean you can have a conversation with them. And the most fun is that you can give them to their parents and get on with your day.”