"Teen Mom 2" star Leah Calvert expecting a baby

"Teen Mom 2" star Leah Calvert has another baby on the way.

The 20-year-old mother and her husband, Jeremy Calvert, 23, are expecting their first child together.

"Jeremy and I are excited to be adding a new addition to our family," she told Us Weekly. "Being a teen mom was difficult, but I'm older and in a different place now -- married to Jeremy and excited for our family to grow."

The reality star, whose maiden name is Messer, was previously married to Corey Simms; he's the father of her twins, Ali and Aleeah. After they split in April 2011, she started dating Calvert. They got married in April 2012.

"Ali and Aleeah can't wait to meet their new brother or sister," she told Us. "We feel incredibly blessed and look forward to this next chapter in our lives."

Calvert thanked her Twitter followers for their support: "THANKS SOOO MUCH EVERYONE! #PositiveTweets makes this momma soooo happy!!! @Calvert505 are in such a good place! Love all of you!"

Season three of "Teen Mom 2" kicks off Nov. 12 on MTV.