As filming gets underway this week in Pittsburgh, the TriStar Pictures and Entertainment One romantic comedy Happiest Season has rounded out its cast for the Kristen Stewart-Mackenzie Davis film.

Joining them in the pic directed and co-written by Clea DuVall is Oscar winning actress Mary Steenburgen, six time Emmy-nominated actor Victor Garber, Golden Globe nominated actress Alison Brie, Independent Spirit Award winning actress Aubrey Plaza and Emmy Award nominee Dan Levy (Schitt’s Creek).

Co-written by Mary Holland, Happiest Season follows a young woman (Stewart) whose plan to propose to her girlfriend (Davis) while at her family’s annual holiday party is upended when she discovers her partner hasn’t yet come out to her conservative parents (played by Steenburgen and Garber). The pic hits theaters on Nov. 20. eOne will distribute the pic in UK and Canada.

Also joining the cast is Ana Gasteyer (The Goldbergs, Saturday Night Live, Wine Country), Burl Moseley (Crazy Ex-Girlfriend), Sarayu Blue (Blockers, To All the Boys: P.S. I Still Love You), Jake McDorman (What We Do in The Shadows) as well as Holland. Marty Bowen and Isaac Klausner are producing. Jonathan McCoy and Wyck Godfrey are EPs.

Steenburgen is repped by UTA, Management 360 and Gang Tyre. Garber is repped by Lou Coulson Associates, Oscars Abrams Zimel & Associates and Industry Entertainment. Brie is repped by Rise Management, WME and A.J. Brandenstein at Sloane, Offer, Weber & Dern. Plaza is repped by MGMT, CAA and Schreck Rose Dapello Adams Berlin & Dunham. Levy is repped by WME, MGMT Entertainment and Morris Yorn.

Gasteyer is repped by the Gersh Agency and Circle of Confusion. Mosely is repped by O’Neill Talent Group and Lara Rosenstock Management. Blue is repped by CAA, D2 Management and Stone, Genow, Smelkinson, Binder & Christopher. McDorman is repped by UTA, Mosaic and Hansen, Jacobson, Teller, Hoberman, Newman, Warren, Richman, Rush & Kaller. Holland is repped by ICM Partners, Atlas Artists and Ziffren Brittenham.