Heidi Montag Shows Off Baby Bump in Black Maxi Dress: '5 Months!'

Heidi Montag and Spencer Pratt attend WE tv Celebrates the 100th Episode of the "Marriage Boot Camp" reality stars franchise and the premiere of "Marriage Boot Camp Family Edition" at SkyBar at the Mondrian Los Angeles on October 10, 2019 in West Hollywood, California
Heidi Montag and Spencer Pratt attend WE tv Celebrates the 100th Episode of the "Marriage Boot Camp" reality stars franchise and the premiere of "Marriage Boot Camp Family Edition" at SkyBar at the Mondrian Los Angeles on October 10, 2019 in West Hollywood, California

Presley Ann/Getty

Heidi Montag Pratt is getting ready to be a mom of two.

On Tuesday, The Hills: New Beginnings star, 35, shared an Instagram photo of herself cradling her baby bump in a black maxi dress. In the snap, Montag Pratt — who is expecting her second baby with husband Spencer Pratt — poses under a floral archway.

"#5months !!!!!!! 💙," she captioned the post.

RELATED: Pregnant Heidi Montag and Spencer Pratt Reveal the Sex of Their Second Baby on the Way

Earlier this month, the couple revealed the sex of their second baby, sharing that they are welcoming another baby boy in an exclusive video for Entertainment Tonight. The couple's new arrival will join their 4-year-old son Gunner Stone.

During the interview, Montag Pratt revealed that she did not expect to be having another son. "My whole intuition is off," she admitted.

The soon-to-be mom of two said that the news is exciting for Gunner, who wanted a little brother. "Growing up I always wanted boys and then recently, I kinda started thinking, I don't know, I kinda want a girl and having one of each," she shared. "For Gunner, he really wants a brother, so, you know, ultimately I want what would be the best for him and his life."

Pratt, 38, expressed his gratitude for making it to this stage of the pregnancy. "We're way past worrying about a gender in my brain. Thank you, God, there's a baby here."

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Montag Pratt confirmed her pregnancy to PEOPLE in early June.

Over the last year, she has been open with her fans about the challenges she's faced as she and Pratt tried to have another child.

She also shared a candid message on Instagram in January about trying for baby No. 2 with Pratt, posting a series of photos with their son Gunner.

RELATED: Heidi Montag and Spencer Pratt's Relationship Timeline

"So thankful for my angel," the reality star captioned the collection of sweet snaps of herself and Gunner at the time. "I never thought it would be so hard trying to have another. I am trusting God's plan and if we only have one I am so thankful for this miracle!"