She then appeared on the 33-year-old's Snapchat where she spoke about how fans assumed that she wasn't at the event. Khloe even called her a "secret little bunny" for staying hidden.
And just when she thought she'd gotten away with it, fans have spotted what looks like a baby bump in the background of Khloe's Christmas Snap.
See that on the far right? Is that a growing baby bump? Fans certainly think so!
“You can definitely see Kylie’s preggo belly on [Khloe’s] snap chat…bottom right with the red nails,” one fan commented on Instagram.
"This video cuts it off but you can definitely see Kylie's preggo belly on [Khloe's] snapchat bottom right with the red nails," writes another.
A version of this article originally appeared on Girlfriend.