Amazon MGM’s plan for Will Smith’s return has never really been about the star — it’s about the company the studio insists on keeping around him. Ever since the streamer and Miramax set their sights on Supermax, they have been outfitting a straightforward prison thriller with the kind of acting pedigree usually reserved for awards-season dramas. Melissa Leo’s arrival is the sharpest expression yet of that instinct: buy prestige, then let it do the heavy lifting.

Leo — an Oscar winner for The Fighter and an Emmy winner besides — joins a cast in which almost everyone carries a trophy or a critics’ favorite on their résumé. Her role is being kept under wraps, but the signing extends a pattern MCM flagged when Jason Clarke came aboard: each new name adds prestige ballast to a Will Smith vehicle that Amazon is otherwise selling on movement and momentum.

David Gordon Green, who directs, has spent a career oscillating between festival minimalism (George Washington), studio comedy (Pineapple Express) and horror reboots (the Halloween trilogy) — a filmmaker comfortable smuggling character actors into genre machinery. Around Smith he now has AnnaSophia Robb, Jaafar Jackson and Nicholas Alexander Chavez, a lineup that reads less like an action ensemble than a repertory company. As Variety first reported, Leo is the latest to sign on.

The calculus is a familiar one for the streaming era. A murder inside a maximum-security prison is pure genre; the surrounding talent is what lets Amazon frame a Prime Video title as an event rather than a content drop. For Smith, still rebuilding theatrical goodwill, being the fixed point in a constellation of respected character actors is its own kind of rehabilitation — the star as the thing everyone else lends gravity to.

Written by David Weil and David J. Rosen, Supermax is shooting in New South Wales, Australia, the film Amazon MGM pried from Miramax in a worldwide deal reported at $70 million and earmarked for Prime Video. Leo’s character may be a secret for now, but the arithmetic isn’t: one more award-winner, one more reason to treat a streaming thriller as prestige.

Tags: casting, Will Smith, Amazon MGM Studios, David Gordon Green, Melissa Leo, Supermax