Maks Chmerkovskiy and Peta Murgatroyd Celebrate Mother's Day Ahead of Third Baby's Arrival

The 'Dancing with the Stars' alums are already parents to sons Rio, 10 months, and Shai, 7

<p>Tiffany Rose</p>

Tiffany Rose

Peta Murgatroyd and Maks Chmerkovskiy are celebrating their last Mother's Day as a family of four!

On Sunday, May 12, the Dancing with the Stars alums shared a series of photos to Murgatroyd's Instagram to show off their Mother's Day celebrations.

In the photos, Murgatroyd, 37, and Chmerkovskiy, 44, pose with their sons Rio John, 9 months, and Shai Aleksander, 7, against a wooded background, walking down a trail. Murgatroyd stuns in a long, white dress with a turtleneck and white boots, and Chmerkovskiy wears a white shirt and gray plaid pants, while the boys dress in neutral earth tones — matching their mom and dad's looks.

"Being a mother is my greatest joy. Happy Mother’s Day 💐," Murgatroyd captioned the post.

<p>Tiffany Rose</p>

Tiffany Rose

Related: Peta Murgatroyd Is Pregnant! Dancer and Maks Chmerkovskiy Expecting Baby Seven Months After Welcoming Second Son

The couple — who first met when they both performed in Burn the Floor on Broadway in 2009 and later tied the knot in July 2017 — have been busy preparing for the arrival of baby number three. Back in March, the pair revealed they are expecting their third boy.

In a video posted to Instagram on March 21, Shai can be seen sitting behind a white cake decorated with question marks, with an edible sign that read, "We're here for the sex!" They can also be seen posing for photos with Murgatroyd's bump, joined by her mom and Chmerkovskiy's parents. Finally, they release confetti poppers in their backyard, revealing the sex of the baby.

"I CANNOT BELIEVE WE WILL HAVE 3 BOYS!! 🤣🤣🤣🤣🤣🤣 Maks and I are beyond happy to have another buddy for Shai and Rio…we want them to be the best of friends and thinking about family dinners already makes us laugh! Not to mention when Rio turns 1, I will give birth to this bundle of joy a couple of weeks later 💃🏼💃🏼💃🏼," Murgatroyd wrote in the post's caption.

<p>Peta Murgatroyd/ Instagram</p>

Peta Murgatroyd/ Instagram

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Just a month after Murgatroyd first announced that she was expecting the couple's third child, Chmerkovskiy revealed during an appearance onThe Jennifer Hudson Show that they were not expecting to become pregnant so soon after welcoming Rio.

Related: Maks Chmerkovskiy Admits Peta Murgatroyd's Third Pregnancy Was a Total 'Surprise'

"I mean, we have a 7-year-old, we have an 8-month-old and Peta’s 5 months pregnant," he told Hudson in March. "So yeah, it was a surprise."

"Oh wow," Hudson replied, to which the dancer said: "Yeah, and that’s the reaction I get 100% of the time. They're like, 'Oh wow.' Like, yes."

Chmerkovskiy also joked that he and Murgatroyd will be close to desperate for a babysitter after their third son is born, telling the host: "I think at some point, when it's 3 [kids], you're like, 'Can anybody come help babysit?' "

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