Matt Damon has played it all from a soldier addicted to heroin in Courage Under Fire to a murderer in The Talented Mr. Ripley to a conjoined twin in Stuck On You to an assassin suffering from amnesia in the Bourne film series. So when he got the news that he would have to actually gain weight to play the role of Mark Whitacre, a food industry president turned FBI informant in Steven Soderbergh’s latest film The Informant!, he was pleased as any 38 year old Oscar-nominated actor could be.

Damon first explained to us what motivated him to do the film and why it was ultimately decided to be done as a dark comedy.

“The only reason I did this movie is for an Oscar nomination, so I’m just going to come out and say it,” he begins jokingly, “Once Steven decided to take it in a more comic direction tonally, it became less important for all of us to do rigorous character studies of the actual people, more about having fun with this terrific script that I wrote, I don’t know who Scott Burns is.”

“We had it for about seven years,” Matt adds, “Scott wrote it seven years ago and we were kind of sitting on it. So it was actually more like a play in the sense that it was really well-written. We would kind of refer back to it once or twice a year. Steven and I worked three times in those intervening years. And we’d always say, yeah, I read it again last night, it’s still really good. And so, in that sense, we examined it enough that all the answers we needed were in the actual text, like when you do the play.”

Matt also explained for us why it was ultimately decided that he had to gain weight for the role.

“Well, I sent him an e-mail that said about two months out, when we were finally getting ready to do it after all this time, I said, why, what do you want this guy to look like physically?” Damon says, “And I sent him this whole kind of long e-mail and it ended with that. He just wrote back, “Doughy,” so that was it, those were my marching orders.”

“But the rationale behind it was, I found out when I got there, I didn’t question it, I just started eating, there’s actually a little prosthetic piece on my nose as well,” he continues, “Steven’s idea was that he didn’t want any hard edges to the character. He wanted him kind of undefined in a way. You can’t quite pin him down. So it’s actually a metaphor for who his character is in the movie.”

He also was candid about how it felt gaining 30 pounds to play a character.

“It actually felt fantastic,” he says, “I never had that much fun making a movie. I just ate whatever I wanted to and thought about nothing but the screenplay and the other actors and it was nice to not think about anything else. Compared to a Jason Bourne movie where it’s like I go home after a day of work and I have to go to the gym. It takes way too much time away from my family. I just prefer to eat.”

“Although I did feel differently, I talked to [Robert] DeNiro before I did it.” Matt adds, “He had done it obviously very famously for Raging Bull. He put on 60 pounds and I asked him about it and he said, well, the first 15 pounds are really fun, and then, he goes, you have to go to work after that. It’s almost true, because I found 30 pounds to be really fun and then, kind of sort of towards the end I was like, I got to get rid of this weight, but I really wasn’t that excited about getting rid of it.”

Matt said that he even enjoyed watching his chubby caricature on screen.

“I can’t get enough of it,” he says, “I’m going to go to every screening. We shoot a lot of over-the-shoulders because if you see my eyes, you see I’m kind of looking away and thinking about other things.”

We asked Damon whether he’s had more fun losing or gaining weight for a role.

“Nowhere near as fun as putting it on,” Matt replies.

Also asked was whether Matt got to meet the real-life Mark Whitacre.

“No, I never met Mark, but I’m going to meet him at the premiere in New York actually,” Damon answers, “He’s seen the movie already and he really likes it.”

One of the hallmarks of the script is the fact that the film is narrated by Damon’s character. Damon discussed with us how he and Stephen Soderbergh came up with the idea.

“Steven called me up and said, ‘Look, they made The Insider already and it’s really good. We don’t want to remake that. So we got to do something that’s tonally different.’” Matt explains, “And he came up with this idea or he and Scott came up with this idea of the unreliable narrator. Steven called me up and told me about it and I started laughing when he told about it.”

“Scott disappeared and in very short order, wrote all of that interior monologue based on his understanding of the character and based on his understanding of the world,” he continues, “Look, we were in Venice a couple of days ago and we were watching it and we’re in the middle of one of those interior monologues. I was sitting with Scott and I turned to him and I said, ‘You are out of your mind.’”

Matt has worked previously with Soderbergh on the enormously successful Ocean’s Eleven film series. We asked the actor, who has worked with plenty of the same producers and directors in his films, whether it’s easy for him to have a more familiar working relationship with his directors.

“Yeah, it just makes it much, much, much easier to do it and I’ve been really lucky with the people that I’ve worked with,” Damon replies, “If I can go back and worked with all the people that I’ve already worked with, I’d be really happy.”

“But, yeah, Steven I’ve worked on with a bunch and more than actually,” he adds, “And Paul [Greengrass] and Gus [Van Sant] and Francis [Ford Coppola]and I went back and worked with him again. I can work with those four guys again. And Clint Eastwood, I going back to work with again, so those five guys I know.”

We asked Damon if he particularly enjoyed working with Scott Bakula.

“I don’t want to really work with Bakula again,” he jokes, “I don’t know about that. And [co-producer] Greg [Jacobs], who he knew, was like, this dude has pictures, we have to do something about this.”

Finally, we asked Damon if he cared to comment on a recent Internet rumor buzzing around about him recently that he had died.

“Why do you guys start that?” he begins jokingly, “I just want some attention. No, it was actually, I had to call my parents and everything. Are we going to start that again? Jesus, such a bitch! No, but that was a really reckless thing to do. The rumor was that I had died, which is, I don’t even know why somebody would think that’s funny, but I know that happened to George [Clooney] a few years ago, when my wife told me that there was an internet rumor that I died. It’s kind of like the scene when the reporter calls Whitacre’s parents, like, ‘Mark’s been telling people that he’s adopted. Hmm, that’s weird.’ That’s kind of like what happened with me and my wife. I said, there’s a rumor on the internet that I died and she said, hmm, that’s weird. But she reminded me that that actually happened to George a few years ago. And I don’t know why.”

“It might be some 15 year-old kid that does it, but I will say Jennifer, my publicist, got all these phone calls from very reputable sources,” Matt continues, “I forwarded the story that if you read it, it just gets sillier and sillier and then, by the end, the guy who said it is quoting the lyrics to “The Fresh Prince Of Bel-Air.” And yet, CNN called, the Boston Globe called, like all of these reputable news sources called and she’s going on, ‘What is going on? Is this true?’ And I said, did you even read the story, and they’re like, ‘Of course, we read it! What’s going on?’ But the amount of misinformation, you can get it around quicker, because you motherfuckers are lazy? That’s why! There, I said it, lazy bastards! That’s why these things spread like wildfire. I think it’s going well. I’m just glad to be here. I’m just going to do interior monologues while you’re talking.”