Agents Of SHIELD’ Star Hopeful For Iron Man Cameo 'At a certain point, it's going to feel right.'

With Reporting by Alex Zalben

“Nothing is impossible.”

That’s the word from Robert Downey Jr. during a Reddit AMA last week, answering the question of whether or not he would ever appear on “Agents of S.H.I.E.L.D.,” the Marvel TV series starring Clark Gregg as Director Phil Coulson. Downey added that there’s “a fair amount of red tape involved in something like that,” but he’s nonetheless thrilled with Gregg’s success.

Likewise, Gregg found himself touched by Downey’s “S.H.I.E.L.D.” shout-out, even if he isn’t entirely convinced that Iron Man needs to swing through Marvel’s small-screen world.

“At the beginning of last season, people wanted to know when the Avengers were going to show up — but this is about the people like Coulson who don’t have superpowers,” Gregg told MTV News at New York Comic Con. “They’re the soldiers and spies who protect people, even though no one ever finds out.”

With its second season well underway, “S.H.I.E.L.D.” has bolstered its ranks with a unique roster of characters that fans have come to know and love. With that in mind, Gregg doesn’t think Coulson needs the support of Earth’s mightiest heroes — but he certainly welcomes it, if the day ever arrives.

“The stuff that [Downey] said about me in support of the show this week was really cool and generous, and felt like the Avengers showing up for me again,” Gregg said. “I hope that sometime, we can work that in.”

Considering reports that Downey is negotiating for an antagonist role in Marvel’s “Civil War” inspired “Captain America 3,” it’s certainly possible that the erstwhile Tony Stark could swing into “S.H.I.E.L.D.” for an episode or two. Even without a direct appearance from one of the Avengers, Gregg believes that events from the Marvel Cinematic Universe will reverberate throughout the TV series as it pushes forward.

“The way that our show crosses over with the Marvel movies, the way it did with ‘Winter Soldier,’ as somebody who is a bit of a fanboy himself, it couldn’t be more exciting,” Gregg said. “At a certain point it’s going to feel right having one of those people there.”