Question: Who plays "Sweet Dee" Reynolds on the Rob McElhenney created comedy? 
Sentence (from "Kaitlin Olson"): She began her career in the Groundlings, an improvisational group in Los Angeles, California, and had minor roles in several television series before being cast as Deandra "Sweet Dee" Reynolds on the FX black comedy series "It's Always Sunny in Philadelphia" in 2005.
Relevant evidence: Yes