“I’m due in January and we are having a boy,” Sliwinska, 32, told People magazine. “We’ve been together for 13 years; married for six. We were both so ready for it and we’ve been planning on this for the past couple of years.”
The couple, who married in 2007, competed in the professional Latin ballroom circuit for years before joining DWTS for its first season in 2005.
Mazo, who was on the show for four years, won the show's first season with partner Kelly Monaco. Sliwinska, with partner Jason Taylor, made it to second place in season six.
She retired in the 10th season writing on her Facebook place that it was "time to think about my future. I’m pursuing my education and looking forward to other projects that perhaps you will hear about, but my main goal is to finish my degree and start building a family.”
On Thursday, Sliwinska again used social media to reveal her pregnancy to her fans.
"There it is, my little secret. Less than 2lbs little :)," she captioned her Instagram photo.