"Stars do get surprisingly rattled," she told PEOPLE Wednesday night, during the magazine's Most Alluring Bodies silent auction in New York City. And even though they didn't all appear in Allure, nude portraits of Angelina Jolie, Gisele Bundchen, Kate Moss and Scarlett Johansson were donated by photographers to benefit Skin Cancer Research.
"We've had some of the most gorgeous people with the most gorgeous bodies really have a moment of crisis when they have to drop the robe," said Wells.
So have there been any major surprises during the nude photoshoots? "Some people haven't discovered the bikini wax," she said. "That was a shock. And that is a very expensive bikini wax when you're [forced to fake it] with a lot of retouching."
They also count on photoshop to keep the pictures strictly PG-13. "Because we want to be on the newsstand, we have to be careful about the raciness," Wells explained. "So we've removed nipples. Mariska Hargitay was rather surprised when she suddenly had no nipples."
In this year's portfolio, Allure also used strategically placed foliage to hide the naughty bits.
"Jennifer Hudson was really great," Wells said. "But she had a moment where she was a little taken aback and she had to wrap her mind around it. And Angie Harmon was surprisingly nervous, but then she pulled it together. They know that we want a beautiful picture. But they still have to take that robe off – they're still naked."
Hilary Duff Keeps it CoveredOne woman who's not naked in May issue? Covergirl Hilary Duff. But the 20-year-old star did show her support during the auction at Splashlight Studios.
The actress hit the event with her boyfriend Mike Comrie, and the two even bid on one portrait – which Duff said would go great in the hockey star's N.Y. pad.
"It's a great picture of a silhouette of a woman," she told PEOPLE. "She's taking her underwear off." (Alas, Duff was outbid.)
So she doesn't mind her boyfriend checking out photos of naked women?
"Of course I don't care," said Duff, before jokingly adding, "Don't stare at it too long!"