The 35-year-old actress and her husband already have two-year-old daughter Penelope
Chlumsky said the couple are planning to go on holiday before their new addition arrives, reported Female First.
Speaking in a Facebook video chat with Travel + Leisure magazine, she said, "Being expecting as I am we're going to take it low-key and try to get a beach vacation in pretty soon.
"I really do try to take a good vacation at least once a year. When my husband and I got married we made a promise to ourselves that we would use our passport at least once a year because we just love doing that.