Jason Merritt/Getty Images(LOS ANGELES) — Mad Men is winding down, and Jessica Paré is already prepping for her next big role: Mom.

The actress is expecting her first child with boyfriend John Kastner, her rep confirmed to ABC News.

Paré, 33, has been dating her musician beau since 2012, according to People.

Kastner made the pregnancy announcement on his Instagram feed a few weeks ago. In the photo, his young daughter, Summer Lee, can be seen wearing a T-shirt with a telling message: “I’m going to be a big sister!”

Neither Paré nor Kastner have confirmed the baby’s due date.

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