You could almost walk by “The Avengers” star Clark Gregg without knowing he’s a movie actor. Not exactly something you could say about Chris Hemsworth of “Thor.”

Sure, you’d wonder, ‘Where do I know that guy with the high forehead from?”

Maybe you’d think it was your high school science teacher, or a guy your girlfriend dated back in college, or someone that stood in front of you in line at Whole Foods.

As Gregg sat across from me at a café table at 55 Gansevoort Street during the Tribeca Film Festival, there’s an instant feeling that we’d known each other forever. That’s because he’s a very good actor, and his forte is playing regular guys – like Agent Phil Coulson.

What’s behind this everyman’s staying power from his first role in “Iron Man” through his expanded story arc in Joss Whedon’s “The Avengers?”

In his characteristically humble way, Gregg told me: “Mostly I’ve been mystified myself.
“I had a tiny role in “Iron Man” but there was a rapport between me and Tony Stark,” Gregg continued. “I grew up reading comics. I could have died right there and been happy. But when Joss Whedon said I was going to be in ‘The Avengers,” I thought my character was going to bring in a java.”
Agent Coulson has a lot more to do in “The Avengers” than carry coffee. Coulson is critical to the storyline. So, talking to Gregg, I was curious: I’d just seen Agent Phil die an apparently grisly death last summer. How was he going to star in Whedon’s TV movie, “Agents of S.H.I.E.L.D?”

“It seemed like I was pretty dead,” nodded Gregg. “I was waiting for a last minute rewrite from the governor!”

But, unlike a “Game of Thrones” character –Sean Bean’s Ned Stark for example – this was not the end for Agent Coulson. Sure, there was a lot of blood, but there was no death rattle, no final shot of eyes wide open. The fans demanded his return — and writer-director Whedon gave them what they wanted.

“There’s something people like about this guy,” said Gregg. “Joss picked up on it. Coulson is a fanboy himself. Whedon fans started this movement – the ‘Coulson Lives’ hashtag. All over the world, fans painted ‘Coulson Lives’ on bridges. It was a kind of civil disobedience. ‘Colson lives; Fury lies.’”

So, how did Coulson survive? Leave it to the comic book conspiracy theorists. “The superhero collector’s cards were in the locker, not on his body, is one of the theories,” said Gregg. “The fact that the fans refusal to let Coulson die was so moving to me. I think it was because he was them: he was the fanboys’ avatar.

“There are people around the Avengers that don’t have their invincibility,” explained Gregg. “These normal folk have to step up, especially when the superheroes were acting like diva bitches.”

At the “Iron Man 3” premiere last night, Whedon confirmed that Agent Phil Coulson survives and stars in the upcoming TV spinoff: “We’ve finished the pilot,” Whedon said. “Agent Coulson is in it. We will explain why in the pilot, and it is wonderful and [Gregg] is phenomenal in it. And we should find out in the very near future whether or not everyone gets to enjoy it as much as we already have.”

Gregg happily discussed Coulson, but on the front burner was the Tribeca Film Festival premiere of his own heroic effort to write, direct and star in “Trust Me,” a dark comedy with Sam Rockwell, Amanda Peet and newcomer Saxon Sharbino.

“It’s the story of a second-string Hollywood agent who finds the next big teen thing,” said Gregg, “and goes to some very dark places to sign her as a client.”

Gregg hatched the idea over the years while working with a couple of young actors. He became “obsessed with the people who handled them, their agents, struggling in Hollywood’s minor leagues. The script came out in this feverish burst. It was more noir and complex and expressed more ambivalent feelings that I have about the star system. I started to write something goofy for fun, and ended up with an aging loser in his fifties desperate to create a break. And, then, I had to play the guy, too.”

Circling back to the world of Marvel, Gregg said, “part of this new story appeals to the Comic Con/”Avengers” crew: this loser agent is so desperate for his last shot that when he finally discovers this prodigious talent, he starts to lose his grip on reality. We are in his head and we start seeing what he sees:  whether it’s fantasy, or the alternative sci-fi vampire movie within a movie.”

If it sounds a little like “The Twilight Saga,” it should. “The movie is like ‘Twilight,’” explained Gregg. “Only it’s classier in that Ang Lee is directing Sir Ben Kingsley and Helen Mirren. Of course, I didn’t have the budget for them, but they’re mentioned.”

Any hopes to hit the award circuit with “Trust Me” like Lee, Kingsley and Mirren? “I’ll take a Razzie,” Gregg joked. “I don’t care.”