Matt Damon put his full trust in Christopher Nolan while filming The Odyssey.

When it came to the pivotal Trojan Horse sequence in the Oscar-winning director’s adaptation of Homer’s poem, Damon, 55, tells PEOPLE that just days before shooting the scene, even Nolan, 55, wasn’t set on how it would be done.

“What was funny about the Trojan Horse was before we shot it, we were filming the fall of Troy, and then the following week we were starting in on the horse,” Damon recalls. “I think it was a Friday and we were shooting the horse on Tuesday and I said, ‘Chris, how are you going to do the horse?’ And he goes, ‘Yeah, I don’t know.’ ”

In the ancient Greek epic’s adaptation, which marks the first film to be filmed entirely in IMAX, Damon plays Odysseus, a warrior king who spends 20 years trying to journey back to Ithaca, where his queen Penelope (Anne Hathaway) and now-grown son Telemachus (Tom Holland) are holding off threats of encroaching suitors jockeying for the empty throne.

Despite not knowing exactly how all of the elements of the sequence were going to work together, Damon says that Nolan let everything unfold organically, as if he were making an independent film.

“The way we were going to shoot the horse was we were all going to get in the horse and figure it out,” he explains. “Hoyte [van Hoytema] is one of the best cinematographers to ever live, and he was going to get in there with us and Chris was going to get in there with us and we had this incredible group of guys [in] the cast.”

“We were together as a crew for the entire film and we just jammed in there and figured it out,” he adds, lauding “all the momentum and the energy you get from just making it real, just not planning it out too much.”

Damon notes one instance when, while filming the Trojan Horse scene, costar Jon Bernthal (who plays Menelaus) was half-submerged in freezing water. He began to shiver so violently — as they shot in the dead of winter in Morocco — that he struggled to speak.

“Jon was so tough,” Damon recalls. “I just have this vivid memory of being above him in the horse and Jon was shaking and putting his hands together and pressing so that he could just get the shivers out so he could get one line of dialogue out.”

When Nolan checked on him, the actor kept steady. “Jon was going, ‘Just go, just go,’ ” says Damon.

“It was early on in the shoot, and I think that set the tone for the cast. The message was like, at some point you’re going to be the guy in the water, and you’re not going to complain about it, you’re going to push as hard as you can until Chris says, ‘That’s enough. Get out, get him warm, get him warm,’ ” Damon says. “So it’s actually a fond memory, thinking about that, even though it was temporarily uncomfortable for Jon, it was a cool example that he set for everybody.”

John Leguizamo, who plays Odysseus’ trusted friend Eumaeus in the film, was also floored by Nolan’s commitment to joining the actors inside the giant wooden horse himself.

“I was looking for Chris Nolan to meet him, and they told me he was inside the horse with 20 actors and the DP [van Hoytema] and the IMAX camera,” Leguizamo, 65, told The Hollywood Reporter, recalling the moment he was supposed to meet Nolan for the first time. “I couldn’t believe that. I was like, ‘Wow, this man is a leader. This man is not going to ask anything of you that he doesn’t attempt himself.’ ”