Hilary Duff and husband Matthew Koma are expecting: 'Surprise Surprise!'

"How I Met Your Father" and "Lizzie McGuire" star Hilary Duff and her husband Matthew Koma are expecting.

The couple announced the news Tuesday on Instagram.

"Surprise Surprise!" Duff captioned a post featuring her family's holiday card, which included sweet images of her kids and Koma.

One side of the holiday card includes the message, "Buckle up Buttercups, we're adding one more to this crazy bunch! The Duff, Bair, Comrie Crew."

Koma also shared a photo of his family on Instagram.

"Baby #4 is loading…" he captioned the post.

This will be Duff's fourth child and her third with Koma. She shares her eldest son, Luca Cruz, 11, with ex-husband Mike Comrie.

Duff and Koma, who tied the knot in December 2019, welcomed daughter Banks Violet, 5, in 2018, and Mae James, 2, in 2021.