Kristen Bell is officially off the market! She has agreed to marry her long-time boyfriend, When in Rome co-star Dax Shepard. According to her spokesperson: "Yes, they are engaged. Over the holidays." So, what has kept this couple going strong for so long? "I've learned the necessity for healthy communication," says Kristen, who provides the voice of the narrator on Gossip Girl. "How important it is to talk about your deepest, darkest fears and feelings," she adds. No word on when exactly Kristen and Dax are planning to walk down the aisle.