Megan Fox is playing coy when it comes to identifying her unborn baby's father.

The 29-year-old actress already shares two sons -- 3-year-old Noah and 2-year-old Bodhi -- with her estranged husband, Brian Austin Green. Though their divorce is not finalized, Fox filed papers to end their marriage in August 2015 citing "irreconcilable differences."

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With the state of Fox and Green's current relationship unclear and the Teenage Mutant Ninja Turtles star debuting an adorable baby bump on the red carpet Monday night, speculation has been swirling over the unborn child’s paternity. Fox couldn't help but have a little fun with the rumors in a cheeky Instagram post on Tuesday.

"#NotTheFather," she captioned a three-way split image, showing current and former co-stars Shia LaBeouf, Will Arnett and Jake Johnson.

Noticeably absent from her "not the father" collage is, of course, Green.

The couple, who tied the knot in 2010, have been spotted spending time together in recent months, often on outings in Los Angeles with their two children. Just last month, though she wasn't wearing her wedding ring, Fox did use the pronoun "we" when discussing her upcoming birthday plans in an interview with ET.

"Maybe go to dinner? I don't know, we never go to dinner," she said. "Maybe dinner, maybe a movie."

See Fox's baby bump on full display in the video below.

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