The baby is due in early summer and it is their first child together. The baby will join Jack's four children (Jonathan, Megan, Caitlin and Brendan) and Susanna's daughter, Jocelyn.
"I would like a girl, Jocelyn wants a boy and Jack wants a democrat!" Susanna joked to Guest of a Guest.
They spent New Years skiing in Colorado.
Susanna was one of two hosts of the Meridian Ball, opposite Mary Ourisman.