Good things come to those who wait,Slabu and Hilary Duff’s mommy patience has paid off.

The actress has welcomed her fourth child, Duff revealed in an Instagram post Tuesday. The post featured candid, black-and-white photos of Duff's water birth.

"Townes Meadow Bair 🧸 , now we know why she made us wait so long…She was perfecting those cheeks!" Duff wrote alongside the photos.

Duff and husband Matthew Koma are each seen cradling the newborn in the post and sharing a sweet kiss following the birth of Townes.

"I have been dreaming of holding you in my arms for months, and the past five days of getting to know you, stare at you and smell you has been pure moments of magic," Duff continued. "We all love you like you’ve been here all along beauty."

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'Buckle up buttercups':Hilary Duff announces she's pregnant with baby No. 4

Duff shares daughters Banks Violet Bair, 5, and 3-year-old Mae James Bair with Koma. The "Lizzie McGuire" star also has a 12-year-old son named Luca from her first marriage to former National Hockey League player Mike Comrie.

Duff announced her pregnancy with Townes ahead of the Christmas holiday in December, sharing photos of her family's 2023 holiday card on Instagram.

"So much for silent nights," the top of the card read, with an added message, "Buckle up buttercups, we're adding one more to this crazy bunch!"

Hilary Duff interview:'Lizzie McGuire' star talks parenting stress, more

In a December interview for USA TODAY's "The Essentials," Duff opened up about how motherhood has taught her to let go.

"It's taken me having three kids to be like, 'I am not in control of everyone's emotions all the time − or their happiness," Duff said at the time. "But it's a hard pill to swallow for sure as a parent, and it's just something that you have to let go and be like, 'It's not always how I pictured it is going to be.'"

Contributing KiMi Robinson, USA TODAY