Chris Pizzello/Invision/AP

Megan Fox surprised the world when she debuted her baby bump at Cinemacon in Las Vegas on Monday, and after media speculation about who the father is, the starlet took to her Instagram to joke about it. That's the spirit!

The 29-year-old actress posted the Instagram image below and simply captioned it, “#notthefather.” It features Fox with co-stars Shia LaBeouf (Transformers), Will Arnett (Teenage Mutant Ninja Turtles) and Jake Johnson (New Girl).

While Fox filed for divorce from estranged husband Brian Austin Green last August after five years of marriage, the two, who are already parents to sons Noah, 3, and Bodhi, 2, have been seen together a number of times since then. They never confirmed that they were back together, so if BAG isn't the daddy, that could be a bit awkward! It's not any of our business, but boy, are we curious!

#notthefather

A photo posted by Megan Fox (@the_native_tiger) on