It's another girl for Kristen Bell and Dax Shepard! Delta Bell Shepard arrived on December 19 and joins big sis Lincoln Bell Shepard, 21 months. The House of Lies and Parenthood stars announced the news via Twitter. "Delta Bell Shepard is here. She doesn't look like either Kristen or me, but we're gonna keep her anyway," Shepard wrote. Added Bell: "The estrogen has now hit critical mass! Good luck, Dax! And welcome to the world, Delta Bell Shepard." The couple went with another normal, but unique baby name. Delta is the triangle-shaped fourth letter of the Greek alphabet that can also refer to the mouth of a river, most famously in Mississippi.