The musician and actor announced on social media on Tuesday that her fourth baby, her third with husband Matthew Koma, is on the way.
The ‘Lizzie McGuire’ star shared a photo of her family’s latest holiday card, featuring a photo of her three kids and husband, Koma.
In the festive family portrait, Duff is also seen with her hand over her baby bump and a shocked expression on her face.
"So much for silent nights," the card read. "Love, the Duff-Bair-Comrie Crew."
The back of the news-breaking holiday card included more images of all three of her kids.
"Buckle up Buttercups, we're adding one more to this crazy bunch!" it said.
Koma also shared the baby news on his own Instagram with the family's holiday photo.
"Baby #4 is loading..." he wrote, tagging the location of the post as "Vasectomy clinic."
Duff shares two daughters with Koma, and her son Luca with ex-husband Mike Comrie.
Duff and Korma met when working on her 2015 album "Breathe In. Breathe Out."
