Third time's a charm for "Teen Mom OG" star Maci Bookout, who just announced she's pregnant again. 

The 24-year-old reality star shared the news on Instagram on Valentine's Day. The picture features Bookout proudly showing off her baby bump alongside fiancé Taylor McKinney.

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"#makingmoremoneys baby boy coming soon! happy valentine's day! @tmon3yyy #lastbutnotleast ," she captioned the sweet snap.

Bookout told MTV that baby No. 3 came as a surprise. "I found out I was pregnant with baby number three right after we got engaged," she said. "It was not expected or a planned pregnancy."

This will be Bookout's second child with McKinney. Their daughter, JC, was born on May 29, 2015. With a due date of May 30 this time around, chances are high the young parents will be dealing with two children under the age of one, especially since Bookout gave birth early the last two times. 

At least now they know what to expect. "Because it's the third one, you know what's going on. You've been there, done that a couple times," Bookout said.

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The young mom first appeared on "16 and Pregnant" with ex Ryan Edwards, when they were expecting their first child, Bentley, a son now 7.