Robert Pattinson couldn't take off his costume on the set of 'The Batman'.

The 35-year-old actor stars as the iconic character in Matt Reeves' blockbuster, and the filmmaker was such a "perfectionist" that Robert couldn't remove his costume.

The Hollywood star told SFX magazine: "I guess in some big movies, people can kind of phone it in. On this, there’s a legacy of really, really good movies - there’s never really been a dud, so everyone brings their A game.

"Also the way Matt directs as well, he’s such a perfectionist. But you’re never really off the set from the second you arrive in the morning. It’s not like you can go back to a trailer or anything. Especially me … I couldn’t even get out of the costume!"

The 'Tenet' star screen-tested in Val Kilmer's 1995 'Batman Forever' costume, and he had to be "drained of liquid" as the thick costume made him sweat so much.

Matt previously spilled: "Rob did his first [screen test] by himself and he literally was wearing, I believe, Val Kilmer's Batsuit.

"Which, by the way, the moment [Pattinson] put it on, that was kind of a crazy moment."

The 'Twilight' star believes it was a combination of the latex-like suit and being "incredibly nervous" that made him sweat so much.

Robert said: "It was crazy. But I remember putting it on and thinking, 'This is impossible. This is going to be absolutely impossible.

"I mean, wearing a kind of two-inch-thick rubber suit, or latex suit, and being incredibly nervous and full of adrenaline the whole time.

"I remember we did like two takes and people were just saying, 'What can we do about the sweat?' They were like, 'Nothing! Nothing that can be done.' I had to be drained of liquid."