Kristen Bell gave birth to a baby girl! Dax Shepard announced the news on Twitter today, writing, "Lincoln Bell Shepard is here. She has mom's beauty and dad's obsession with breasts. Hooray!" Kristen later tweeted her own message: "My new roomate poops her pants and doesn't pay rent...basically Dax Shepard pre-sobriety. Welcome baby Lincoln xo." Congrats to the new family of three!