Mr. Big, Irish American actor Chris Noth, had to undergo radical boot camp surgery to shed 20 pounds for his bedroom scenes in "Sex and the City 2."

Producers told him a body double would be needed if he didn't drop the weight quickly, according to the Daily Mail.

Noth went to a boot camp in Brazil for several weeks to lose the extra poundage -- and succeeded just in time.

"Luckily Chris’s weight loss was sufficient and a stand-in wasn’t required," says an insider.

"He did really well to lose it and is proud that his cheeks will now be seen by millions of 'Sex and the City' fans."