Kaitlin Olson and Rob Riggle have joined the upcoming Rob McElhenney-Rob Rosell multi-cam pilot currently in the works at Fox.

Olson and Riggle join previously announced cast member Leah Remini. The series follows the unconventional family set up of a woman (Remini), her new wife (Olson), and her ex-husband (Riggle), and two kids all living under their same roof.

Olson most recently starred in the recently canceled Fox single-cam comedy “The Mick.” In addition to starring in “The Mick,” Olson is also one of the stars of the long-running FXX comedy “It’s Always Sunny in Philadelphia,” which McElhenney co-created and on which Rosell previously served as a writer and executive producer. Olson and McElhenney are also married, having met on “It’s Always Sunny” and tying the knot in 2008.

She is repped by UTA and Haven Entertainment.

A decorated Marine before becoming an actor, Riggle is known for his work in hit comedy films like “The Hangover,” “The Other Guys,” “21 Jump Street,” “22 Jump Street,” and “Step Brothers,” as well as his stints on “Saturday Night Live” and “The Daily Show with Jon Stewart.”

He is repped by WME, Artists First, and Sloane, Offer, Weber & Dern LLP.

Fox ordered the project off cycle. McElhenney and Rosell will serve as writers and executive producers on the project. Fellow “It’s Always Sunny” co-stars Charlie Day and Glenn Howerton will also executive produce, along with “It’s Always Sunny” executive producer Nick Frenkel. 20th Century Fox Television, where Rosell is under an overall deal, will produce.

The project will be in consideration for a potential mid-season launch should Fox order it to series.