Matthew Rhys is going from stealing America’s secrets to embodying one of its icons.

Fresh off his Emmy-winning six-season run on FX’s The Americans, Rhys has signed on to star as legendary fictional criminal defense lawyer Perry Mason in a prospective limited series at HBO. The project is being exec produced Robert Downey Jr., who was originally eyed to play Mason. (Downey Jr.’s Team Downey shingle has been trying to get a Perry Mason project off the ground for much of the past decade.)

Rhys, who will also serve as a producer on the project, will play Mason at a time in his life when he is living check-to-check as a low-rent private investigator. He also finds himself haunted by his wartime experiences in France and is suffering the effects of a broken marriage.

Rolin Jones (The Exorcist) and Ron Fitzgerald (Westworld) will pen the adaptation and serve as co-showrunners and exec producers. Additional EPs include Susan Downey, Amanda Burrell and Joe Horacek.

Here’s the project’s logline:

1932, Los Angeles. While the rest of the country recovers from the Great Depression, this city is booming! Oil! Olympic Games! Talking Pictures! Evangelical Fervor! And a child kidnapping gone very, very wrong! Based on characters created by Erle Stanley Gardner, this limited series follows the origins of American Fiction’s most legendary criminal defense lawyer, Perry Mason. When the case of the decade breaks down his door, Mason’s relentless pursuit of the truth reveals a fractured city and just maybe, a pathway to redemption for himself.

The search is on for a director to helm the limited series.

Perry Mason was most famously played by late actor Raymond Burr, who starred as the defense attorney for nine seasons on CBS’ Perry Mason series (1957–1966) and 26 subsequent TV movies (1985–1993).