The stars hit the red carpet Monday night for the world premiere of Iron Man 2 at the El Capitan theater in Hollywood, and RadarOnline.com was front-and-center.

Iron Man's main man Robert Downey Jr. -- who reprises his role as billionaire adventurer Tony Stark -- was the 'belle of the ball', and all of the stars gushed about how great it was working with him. Still, many told us they didn't want his iron man heart! ( Who can blame them?)

The legendary Hugh Hefner showed up with only one blonde in tow, but, surprisingly, he's not impressed by Iron Man! When asked what he'd do with Iron Man's heart, he quipped: "I'd never want to trade places with Iron Man".

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• Don Cheadle
• El Capitan Theater
• exclusive
• Iron Man 2
• premiere
• Red Carpet
• Robert Downey Jr.
• Samuel Jackson
• Scarlett Johansson
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