The ‘Red Rocket’ star joins Tim Blake Nelson and Vera Farmiga in the true-crime drama about the religious cult behind a 1997 mass suicide, being sold by The Exchange.

The Leader, the upcoming biopic about the Heaven’s Gate cult set to star Tim Blake Nelson and Vera Farmiga, has lured another big-name follower.

The Hollywood Reporter can reveal that Simon Rex has joined the real-life crime drama, unveiled earlier this week at the European Film Market in Berlin, where The Exchange is introducing the project to buyers.

Farmiga and Nelson are set to play Ti and Do, the founders of the UFO cult that in 1997 committed the largest mass suicide to ever take place on American soil. THR understands that Rex — who received critical acclaim for the Cannes-bowing Red Rocket and recently wrapped production on Zoe Kravitz’s directorial debut Pussy Island, one of several upcoming roles — will play a key devotee of the religion who faces devastating consequences when he falls in love with a fellow cult member.

“Simon Rex is the perfect actor to inhabit this humorous, complex, and haunting role” said The Leader writer-director Michael Gallagher. “We are thrilled with the stellar cast that is bringing this human story to life.”

The film — which will track Ti and Do as they develop Heaven’s Gate, build a devout following and face unforeseen conflict when the spaceship they believed would transport their resurrected selves to heaven fails to arrive — is being produced by Cinemand and Balcony 9 Productions, with Jana Winternitz, Michael Wormser and Gallagher producing for Cinemand, and Joel David Moore and Max Osswald for Balcony 9. Rishi Bajaj and Daniel Taborga from Balcony 9 will executive produce along with Cassian Elwes, Evan Silverberg and Entertainment 360.

“Simon Rex’s acting skills will add patina to this very strong and commercial project,“ said Nat McCormick, worldwide sales and distribution president at The Exchange.

Rex is represented by Buchwald, Range Media Partners and Narrative.

The Exchange’s EFM lineup includes Orlando Bloom’s The Cut, Octavia Spencer, Joseph Gordon-Levitt and Lucy Liu’s Nobody Nothing Nowhere, Jeffrey Dean Morgan and Guy Pearce’s Neponset Circle, Olivia Munn’s Replay, Kathy Bates’ Thelma, Zoe Saldana and Garrett Hedlund’s The Absence Of Eden, Venice 2022 competition entry Monica, Steve Zahn and John Magaro’s LaRoy, as well as Tyrese Gibson and Thomas Jane’s Bosco.