Mary Elizabeth Ellis is an American actress. She is best known for her role as The Waitress on the FX comedy series Its Always Sunny in Philadelphia. She has also starred in the NBC sitcom Perfect Couples and the Fox sitcom The Grinder.
Ellis married her Its Always Sunny in Philadelphia costar Charlie Day on March 4, 2006. Their first child, a son named Russell Wallace Day, was born on December 15, 2011.
Source: Wikipedia