Allure magazine's annual "Nude" issue will hit stands on April 29th, but we already know which stars dropped their skivvies.

Minnie Driver, 44, Nia Long, 43, Jenna Dewan Tatum, 33 and Kristen Bell, 33, are the lovely ladies who agreed to pose in all their God given glory for the glossy beauty book.

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They all look great, of course, but you have to wonder (I do anyway) what would "make" someone bare their souls (and everything) else for the whole world to see? It's not like a honking paycheck was the draw -- editorial layouts of celebrities are typically non-paying gigs -- so, what was the driving factor?

Kristen Bell, who's riding high on the mind-boggling success of "Frozen" and feeling the love from diehard "Veronica Mars" fans since the movie's release late last month, felt compelled to open up about her decision making process.

Mrs. Dax Shephard could surely have bowed out -- she'd just given birth for crike's sake -- but, no, she wanted to do it, felt compelled to in fact.

"I talk a big game about being comfortable no matter my size. I wanted to put my money where my mouth was," the "House of Lies" star says in Allure and maintains that she's cool with whomever should happen to lay eyes on the photos. "I'm not concerned with anyone. I hope it's not misinterpreted, but that's too big of a problem for me to actually think about."

Bell says that she started doing Pilates after giving birth to daughter Lincoln, now 1. "I started doing Pilates, then I realized it wasn't as torturous as regular cardio, so I've kept it up. I'm more in shape now than I've been at other times in my life."

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