"Mickey Rourke's got the body for it," he said at the junket for his latest film, "The Soloist." "He'll be playing my nemesis."
But Rourke's role won't be the standard comic book villain.
"We're going to try to do something a little different with the story line and really flesh out the bad guy," he said. "Usually in a superhero movie, it's this kind of two-dimensional thing, and if you have Mickey Rourke, you might as well make it more interesting and cerebral and visceral. I think we're gonna play very well off each other."
And, he added, co-star Scarlett Johannson is also ready to step into her tights as Russian agent the Black Widow.
"I didn't need to give her any tips, she's in rocking shape," Robert added.
The superhero sequel starts filming on Monday, but on Thursday, Robert was still enjoying a big year that shows no signs of slowing down.
"I thought 2008 was my year, and now it's 2009 and people are going, 'Robert, it's your year' — I go, you know what? I let them keep saying that," he said.
And it hasn't just been a good time for his movie career.
"You're having like a Patrick Dempsey hair year," Nancy told him.
"Wow, I don't know what to say," Robert responded. "I saw him driving his daughter to school the other morning. It was 8 in the morning, his hair looked awesome."
In "The Soloist," Robert gets more serious, playing Los Angeles Times journalist Steve Lopez in the real-life story of his friendship with a homeless musician, played by Jamie Foxx.
"I think it's a tough job, and an underrated job," Robert said of journalism. He's played several reporters over the years, including Joe Wershba in 2005 broadcast room drama "Good Night, and Good Luck."
"I love reading the newspaper," he said, adding that he doesn't worry about bloggers or paparazzi. "If you're up in my face and you're gonna do some creepy stuff, I pity you."
As for his Guy Ritchie-directed turn as Sherlock Holmes, Robert hit the gym – and told Nancy that the film stayed true to the original Arthur Conan Doyle stories.
"He was a bad ass," Robert said.
The film features him doing martial arts, which he's done for five years, long before his "Sherlock" role – but he said the now-famous shirtless photo of him in character took some extra work.
"I had starved myself, and worked out to a point where I could look like that for six hours," he said.
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