Reality TV star Jason Wahler and his wife, Ashley Wahler, arrive for the 42nd Annual Maple Ball at the Montage Hotel on Oct. 26, 2016, in Beverly Hills. Credit: Greg Doherty/Getty Images

Think pink! The Hills alum Jason Wahler and his wife, Ashley Slack, revealed on Instagram on Sunday, March 5, that they're expecting a baby girl.

The parents-to-be, who wed in October 2013, hosted a gender-reveal party at their home with their closest friends and family members to announce the sex of their baby. In a video shared on Wahler's account, the couple ask their guests to place their final bets on whether the baby is a boy or a girl.

"We want to thank all of you guys for being here, though, seriously," the former MTV star, 30, said while donning a blue ribbon on his shirt, hinting that he was hoping his first child would be a boy. His pregnant wife, meanwhile, wore a pink button on her cardigan.

Slack then stuck a pin into a giant black balloon in the middle of their kitchen. As the balloon popped, numerous small pink balloons flew out, revealing that the pair are expecting a daughter.

Boy or girl????

A post shared by Jason Wahler (@jasonwahler) on

When Wahler and Slack announced last month that they were expecting their first bundle of joy, they told Entertainment Tonight that they already knew the sex of their baby, but decided not to reveal the news just yet.

"We are so overjoyed and excited for this baby!" they told the news outlet on February 21. "We absolutely love kids and are so happy to finally be starting a family of our own."

Wahler is the third Hills alum this year to announce that their family is expanding. His ex Lauren Conrad announced in January that she and husband William Tell are expecting, and Conrad's BFF Whitney Port announced in February that she and husband Tim Rosenman will have their first baby.

In fact, the Wahlers learned of their pregnancy on the same day Conrad, 31, announced hers. "This is so funny — so we found out the morning of New Year's Day," Slack exclusively told Us Weekly. "Then I saw that Lauren was pregnant that same day ... and I was laughing, because I'm like, 'Oh, my gosh, that's so funny that it just happened all at the same time.'"

Wahler and Slack's little girl is due in August.

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