McKenna Grace and Paul Walter Hauser Team Up Again for 'The Official Mistress'

McKenna Grace and Paul Walter Hauser are taking their collaboration beyond television. The pair, who are set to star in an upcoming live-action Scooby-Doo series, have now been cast together in the new feature film The Official Mistress.

The 19-year-old actress and 39-year-old Emmy-winning actor join Louis Partridge in the revisionist romantic comedy, which explores the twilight of the French monarchy. Matt Brown wrote and directs the project.

The film follows King Louis XVI, portrayed by Walter Hauser, as the last king of France pursuing Comtesse Madeleine de Vascone, played by Grace, who holds the title of La Maîtresse-en-Titre—the Official Mistress. The king seeks this arrangement to counter whispers about his virility from both the country and court. Meanwhile, Rene Rennault, a lowborn cook played by Partridge, takes on the dangerous role of the King's Taster in hopes of saving his first love, Madeleine, risking accusations of treason in the process.

Producers are still casting for Marie Antoinette and other key roles including De Conte, D'Artois, Jacques, and Luc.

Production is scheduled to begin in September across European locations. The project is launching its worldwide sales campaign at Cannes, coinciding with the opening of the 2026 Cannes Film Festival.

On the Scooby-Doo front, Grace plays Daphne Blake. Hauser's role in the series remains undisclosed, though speculation has centered on the possibility he may voice Scooby. Tanner Hagen has been cast as Shaggy.