Source: Bang Showbiz NewsKristen Bell is pregnant with her first child by her comedian fiance Dax Shepard. The 'Forgetting Sarah Marshall' actress is expecting her first child with her fiance Dax Shepard, 37, who handily stars in the show 'Parenthood'.A source told People.com: "They're so excited - they're both ecstatic. They can't wait to become parents"Kristen had a little bit of morning sickness early on but she just started shooting the second season of 'House of Lies' and is feeling great now."The couple got engaged in 2009, after dating for two years. They have starred in films together, including 'When in Rome' and 'Hit and Run'.Earlier this year, Kristen and Dax revealed they were planning to start a family, but have previously said they don't want to tie the knot until gay marriage was legal in the state of California, where they live. In February, Kristen, 32, said: "The reason we're not rushing to get married is because I don't feel appropriate taking advantage of a right that's denied to my [gay and lesbian] friends. "That's why we've been so hesitant. Dax and I have talked about it a lot, and this issue is very important to both of us. We're just standing up for what we believe in."