'You're the Worst' to Introduce Jimmy's Three Sisters (Exclusive)

You're The Worst - H 2015
Byron Cohen/FX

FXX's You're the Worst is going to introduce Jimmy's (Chris Geere) family in season two.

The comedy from showrunner Stephen Falk has cast Jayne Entwistle, Jessica Chaffin and Katie Costick to play Jimmy's adult siblings, The Hollywood Reporter has learned. 

The trio will appear in the "A Right Proper Story" episode, which will also introduce Jimmy's father, Ronny (played by The Inbetweeners' David Schaal). An air date has not yet been determined. (Get a first look at the whole dysfunctional family, above.)

Entwistle (Desperate Housewives) will play Fiona, Jimmy’s older sister. She has a singular focus in life: her job at the local Tesco grocery store. Her life is thrown into a tizzy when she’s introduced to a fancy American grocery store, leading her to question everything she holds dear. The actress is repped by The 5 and Origin Talent.

Chaffin (Spy) will play Di, Jimmy’s middle sister, an aggressive, track suit-wearing bully who is always looking to start a fight. She’s responsible for giving Jimmy his hated childhood nickname. She's repped by CAA, MGMT and Morris Yorn.

Costick (Drawn) will play Lilly, Jimmy’s youngest sister, the sweetest of the bunch. A naive, good-hearted lover of Harry Potter she's the Cinderella to her older sisters. She's repped by Metropolitan Talent Agency.

Falk said season two would also explore more about Jimmy's background. "His family is English white trash in a way, and he immediately wanted to distance himself from his tiny little industrial, lead-mining town and take on this posh accent and immediately go to London and L.A. as soon as he could and get far away from his roots and reinvent himself. But as we'll sort of learn, the past always comes back to haunt you," Falk told THR.

The trio join a growing guest list for YTW season two that also includes Justin Kirk, Tara Summers, Collette Wolfe as Edgar's (Desmin Borges) new friend; The Office's Andy Buckley as Jimmy's (Chris Geere) agent; and Mageina Tovah as Paul's (Allan McLeod) new love interest.

Season two of YTW, which will also feature a rap feud, premieres Sept. 9 at 10:30 p.m. on FXX. For more scoop, check out our deep dive interview with Falk about season two here