Patrick Mahomes knows a thing or two about Xs and Os ... so it's no surprise he and wife Brittany played an adorable game of tic-tac-toe with their 2 tots to reveal the gender of baby #3!
The Mahomeses posted video of the reveal -- which looks to have taken place at their palatial Kansas City estate -- to their Insta accounts, captioning it ... “Baby Mahomes #3 is a….”
In the vid, their 3-year-old daughter Sterling turns over tiles to see if she'll be getting a "Little Sis" or "Little Bro" .