When it comes to the highly confidential world of the Marvel Cinematic Universe, some of its stars are better at keeping secrets than others. For example, Marvel Studios didn't even let Tom Holland read the entire Avengers: Infinity War script — and he's Spider-Man.

Actor Sebastian Stan joined the list of Marvel's Worst Secret-Keepers earlier this month when he signed a Captain America: The Winter Soldier poster for a young fan and may or may not have spoiled Cap's Infinity War fate in the process. He not only drew a beard on Steve Rogers's face — matching the one the character sports in the forthcoming superhero flick — but he also added a speech bubble that read, "Argh, I'm Nomad." Of course many fans then took that to mean that Steve Rogers would become his jaded alternate identity Nomad in the anticipated film.

However, as Stan recently explained to MTV News, he wasn't even the first person to come up with that.

"Somebody else had gone out and said, 'He's Nomad,'" Stan told MTV News correspondent Josh Horowitz while promoting his latest film I, Tonya in New York City. Though, that doesn't mean he's done trolling fans. "He is missing the star on his chest," Stan added with a bit of mirth in his eyes. "So I don't know what that means." (He's also curiously missing his shield.)

To be fair, with production of Avengers 4 still ongoing in Atlanta, Stan could be telling the truth. After all, he only knows what the filmmakers Joe and Anthony Russo want him to know. He doesn't even get a script until the day of filming.

While Stan can't divulge too many details about Bucky Barnes's role in Infinity War, he is content with his overall arc (so far). "My job there is to serve the bigger story," Stan said, "But there is an arc there for him."