The "Orange Is the New Black" star broke the news to fans in a post on Instagram on Thursday, October 24, sharing a photo of her baby bump, while holding the couple's two-year-old daughter, Ella.
"We are so excited to announce that our family is growing," Prepon captioned the sweet snap. "Life is beautiful! #knockedup."
The actors, who had been longtime friends, began dating in 2016 and wed in June, 2018, 10 months after the birth of their little girl.