Cavallari is pregnant with their second baby. The 26-year-old former star of MTV's "Laguna Beach" and "The Hills" confirmed the news Wednesday on Twitter. She wrote: "We are so excited for Camden to be a big brother!"
Camden is the couple's 14-month-old son.
Cavallari and Cutler were married last June in Nashville, Tenn.
The family splits their time between Nashville and Chicago.