Kate Winslet is returning to HBO, but she’s a long way from Easttown.

The Oscar-winning actor is leading the upcoming HBO limited series “The Regime,” which was teased during the April 12 Warner Bros. Discovery streaming press event.

The lush teaser is filled with mystery and political intrigue, and the official logline doesn’t give too many clues, simply saying that the series “tells the story of one year within the walls of the palace of a modern European regime as it begins to unravel.”

The cast includes Matthias Schoenaerts, Guillaume Gallienne, Andrea Riseborough, Martha Plimpton, Hugh Grant, Danny Webb, David Bamber, Henry Goodman, Stanley Townsend, Louie Mynett, Rory Keenan, Karl Markovics and Pippa Haywood.

The series was formerly known as “The Palace.” Stephen Frears and Jessica Hobbs are directing the series, which is written by Will Tracy, who is also executive producer and showrunner. Executive producers include Winslet, Frears,...