Hilary Duff doesn't yet have the Bakers' dozen.
After all, the Lizzie McGuire alum revealed Dec. 12 she's pregnant and expecting her fourth baby, her third with husband Matthew Koma.
"Surprise Surprise!" Duff wrote on Instagram alongside her family holiday card, which read, "So much for silent night" and "Buckle up Buttercups, we're adding one more to this crazy bunch!"
And call us crazy pops, but it was her former Cheaper By the Dozen costar who had the perfect reaction to the news.
"Just 8 more to complete the pack," Alyson Stoner wrote, prompting Duff to reply back, "Ha well played."
Fans also gave their seal of approval to Stoner's joke, with one user commenting, "THIS WINS THE INTERNET."
Duff and Stoner costarred as sisters Lorraine and Sarah Baker in Shawn Levy's 2003 comedy and its 2005 sequel, which centered on Illinois couple Tom Baker (Steve Martin) and Kate Baker (Bonnie Hunt) and their 12 prankster kids.
And though Duff is expecting her house to get a little more rowdy with the new addition, she probably isn't at risk of having her underwear soaked in meat.
Rounding out her quarter-dozen are son Luca, 11, who she shares with ex-husband Mike Comrie, and her and Koma's daughters Banks, 5, and Mae, 2.
Koma is also emotional about growing their clan, writing on social media alongside more photos from the family maternity shoot, "baby #4 is loading..."
In the meantime, Duff couldn't be happier to wake up, wake up with the "Kisses Back" artist.
"Everything is just better with …and because of you," she wrote on Instagram in June, while wishing him a Happy Father's Day. "We love you beyond and thanks for always carrying all the stuff I pack."
To see what Duff and Koma's dreams are made of, read on for this look inside their own Cinderella story: