Here's where else you may have seen Jumanji: The Next Level) was added to the cast as Dennis and Dee's father Frank to add a little star power.
Despite the show's gleefully nihilistic tone, It's Always Sunny In Philadelphia has run for over thirteen seasons thus far, making it one of the longest-running sitcoms of all time. Despite running for over a decade the show is still frequently hilarious, with the gang constantly finding new ways to be despicable human beings. The show's fourteenth season will arrive in September 2019.
Kaitlin Olson is a key member of It's Always Sunny In Philadelphia's cast, with Dee being no less horrible than the rest of the Paddy's Pub crew. The actress has a busy career outside of the bar and appeared in The Drew Carey Show and movies like Coyote Ugly prior to ing It's Always Sunny In Philadelphia.
In the years that followed the sitcom's success, Kaitlin Olson appeared in guest roles on shows like The Riches and Vacation, a soft reboot of the popular Chevy Chase comedy franchise.
In 2016 she loaned her voice to Pixar's The Simpsons. She also reprised Destiny for video game Disney Infinity 3.0. In 2017 she took the lead role in Fox sitcom The Mick, playing the irresponsible aunt to two rich, snobby kids who is forced to take care of them after their parents flee the country. The show ultimately ran for two seasons before being canceled and while reviews were mixed, Olson received praise for his performance.
In 2018, Kaitlin Olson also appeared in dark comedy Arizona alongside Danny McBride and Luke Wilson. There are no plans for It's Always Sunny In Philadelphia beyond season 14, but it wouldn't be a surprise if the show kept going beyond that.