The former Kenan & Kel star, 38, announced on Tuesday that he and his wife, Asia Lee, are expecting their first child together.
"We have a bun in the oven!" Mitchell wrote on Instagram. "Thank you @therealasialee for being the best wife to me, the best friend to me and now the mom to our blessed baby!! I love you so much!"
The post was full of '90s Nickelodeon nostalgia, as the happy couple donned Good Burger hats and held orange soda (the favorite drink of Kel's TV alter ego) while posing against an orange background.
While this is the first child for Mitchell and Lee, the actor is already a father to 17-year-old son Lyric, and 15-year-old daughter Allure.
Mitchell recently appeared dressed as his Good Burger character, Ed, at Super Bowl LI.