[This story contains spoilers from the season premiere of The Righteous Gemstones, “Prelude.”]

Fans of The Righteous Gemstones who tuned into Sunday’s season four premiere were probably anticipating more of what they expect from the show: commercialized Christianity, well-timed dick jokes and an undercurrent of criminal activity that makes each season unpredictable.

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Well, there may have been some nefarious behavior but it was back in the 1860s. The final run of Danny McBride and Jody Hill’s HBO comedy kicked off with a standalone Civil War period piece starring Bradley Cooper as the first Gemstone to put on a clergy robe — albeit in the most unscrupulous of ways. The story of Elijah Gemstone drinking and scamming his way out of trouble as the South succumbed to Union forces, and Cooper’s casting in particular, has been a well-guarded secret in the run up to the episode’s March 9 debut. Even a paparazzi shot of the 12-time Oscar nominee in a Baby Billy’s Bible Bonkers t-shirt didn’t tip anybody off.

“I’m so used to showrunning, acting, doing all the things,” says McBride, who directed and co-wrote the episode, which features neither himself or any of the Gemstones cast. “You go a little bit nuts keeping all the plates spinning. Here, I was just able to focus on directing and creating that camaraderie with Bradley. You had a partner in crime to pull off something like this.”

McBride hopped on the phone earlier in March to talk about the unconventional start to the final season and why Cooper never having watched the series turned out to be a real blessing.

You’ve either been wanting to do this forever or it just came to you out of the blue. Which is it?

It’s a combination. I grew up in Spotsylvania County, Virginia. There was a lot of Civil War action there, and I’d find old bullets and things like that in my backyard when I was a kid. So, I’ve always been fascinated with history, just because I had context for it. When it came time to kick off this final season, I thought it would fitting to tell a story about where the Gemstones came from. No one said “no,” so we just kept pushing forward.

I’d imagine the impulse was to either stunt cast or just put someone in your existing cast in old-timey clothes. How did you land where you did?

The episode is obviously a big swing. It’s not what the Gemstones audience is showing up for. By kicking off this season without any of the cast, it was going to take somebody special to make that land. We didn’t want the episode to feel like a joke. We wanted it to stand on its own, have its own tone and feel somewhat real. So we wrote it, and then it was like, “Well damn, who can do this? Who is the audience going to want to see?”

Bradley Cooper.

I threw it off the cuff to my producing partners… “It needs to be somebody really good, somebody with charisma who everybody likes — someone who’s really good, has charisma and that everyone likes. Someone like Bradley Cooper.” One of the producers was like, “Why don’t we just ask him?” I assumed that Bradley Cooper’s not going to want to come down to Charleston for no money and be in a Civil War period piece, but I was wrong. We sent him the script and he instantly got back to me. He dug the material and was flattered we asked. I never thought we’d get a guy of his stature to wear a period piece wool costume in 90 degree weather for 10 days straight. And for no money. It takes a very dedicated person to commit to that.

Bradley Cooper as Elijah Gemstone.

Was he a fan of the show?

When we cast him in it, he told me he had never seen it before and that he wanted to hold off until we were done shooting. He didn’t want anything to influence his performance or his take on it. Sometimes, when you bring a heavy hitter to be a guest star, they end up doing an impression of the people that are already on the show. They want to score laughs the way that people normally do. So, I thought it was smart of him to identify that watching the show could be a pitfall.

You would’ve gotten a completely different performance.

It really would’ve been. But what’s cool in watching it now, he still feels like a Gemstone to me.

What’s the shared DNA for you?

All of the Gemstones are scoundrels. They’re devious and not the most upstanding citizens. That’s a tricky thing to pull off. We’re lucky in a show that we have really talented actors who can walk that line, whether it’s Walton Goggins or Edi Patterson or Mr. Goodman or Adam Devine. There’s a charm and a charisma to all of them where you still root for them even if what they’re doing is kind of despicable. Bradley has a charm that is very disarming. It’s tall order. He’s playing a Confederate soldier and you’re supposed to root for him by the end of the story.

There’s been this debate since the first season of whether this show is a comedy or closer to family drama like Succession. This certainly feeds into the latter. Do you like playing with that tone?

At the end of the day, as ridiculous as the show can be, our goal in it is to land the plane on planet Earth. This stuff has to resonate and have emotional impact. It’s a trick that we have to execute in the scripts, but a lot of the onus is on the performers. That’s the MO of what we’re trying to do. This episode is an extension of that. For as silly as the show can be, we try to push ourselves to land something that’s a little bit outside the reach of what we’ve tried before.

Is this the most expensive episode?

You know what? I don’t think it is, surprisingly enough. We shot this entire thing in a little less than 10 days. Everything was daylight dependent, except for a handful of scenes. We had to be super efficient and super practical with how we pulled it off. Not to keep singing Bradley’s praises, but there was no room for error and he was prepared to work that way.

What did Amy Gravitt say when you pitched this idea? There are precious few episodes of this show left.

I didn’t want to pitch it. (Laughs.) I executed the script and sent it to them blind. On its surface, this shouldn’t work. We were going to be up against that, so I felt like it was better if they were able to judge the fully realized idea. To her credit, she was excited about the project is the same that we were. These things are challenging to land, but that’s part of why we do them.

Any concerns about confusing your audience or does that make it more exciting to you?

It just makes it more exciting to me. One of the things about the show that we’ve pushed ourselves to do creatively is just to keep audiences on their toes, to never really know what the formula of the show is. Doing something like this in the final season, it just felt like another way to bring the audience in and let them know that anything can happen. Just because they’ve seen three seasons of the show already, they might not know all the tricks we have up our sleeves.

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