Kaitlin Olson portrays Dee Reynolds on It's Always Sunny in Philadelphia. She has appeared in almost every episode of the series, with the lone exception being season 4's "Mac's Banging the Waitress". Kaitlin was born in Oregon and studied theater at the University of Oregon. After moving to Los Angeles, Kaitlin joined The Groundlings which led her to many film and television acting opportunities. She has also performed improv on Whose Line Is It Anyway? and Kelsey Grammar's short-lived sketch show. Kaitlin joined the cast on Sunny in 2005, and at some time in 2006 she and Rob McElhenney began dating. They were engaged in 2007 and married on September 27, 2008. Kaitlin was pregnant during the filming of Season 6 and the writers included her pregnancy into the series. She gave birth on September 1, 2010 to Axel Lee McElhenney. The couple's second son, Leo Grey McElhenney, was born on April 5, 2012. They also have a dog named Oscar.