Laura Prepon and Ben Foster Expecting First Child Together

Laura Prepon is going to be a mom!

The Orange Is the New Black star, 36, and her fiancé Ben Foster are expecting their first child together, a source confirmed to PEOPLE.

The couple attended the Creative Coalition's annual Spotlight Awards at the Sundance Film Festival on Sunday and stayed mostly to themselves all night.

"Ben seemed really protective and kept very close to Laura the entire night. He was holding on to her arm as they walked in and kept by her side during the dinner," an onlooker tells PEOPLE. "Neither of them got up much to mingle. They definitely enjoyed dinner. I noticed she finished her plate."

The couple, who have known each other for over 18 years, announced their engagement back in October.

Congratulations to the happy couple!

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This article originally appeared on Womanista.com