Who’s your daddy?!

Just days after Megan Fox shocked the world with her pregnancy news — by stepping out with a baby bump months after her divorce from Brian Austin Green, she made a joke about paternity on Instagram.

She captioned a collage of three male costars — Shia LaBeouf, Will Arnett and Jake Johnson — with a single hashtag: “#NotTheFather.”

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#notthefather

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Soo, who is the father?

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So far, she’s remained mum (no pun intended) on the whole thing. Although many believe it’s her ex, who happens to be the father of her two sons, Noah, 3, and Bodhi, 2.

megan fox brian austin green getty images

Sources close to the couple tells TMZ that Brian is in deed the father — but that the new bundle of joy will not change their plans to divorce.

The report explains that the pregnant 29-year-old is the “breadwinner,” and axing the divorce would mean any earnings she’s made since filing for divorce (such as her paycheck from the new Teenage Mutant Ninja Turtles flick) would be divided between the spouses.