Christina Aguilera and talk show host Ellen DeGeneres Credit: Michael Rozman/Warner Bros.

There's a very simple reason as to why Christina Aguilera appears nude on the cover of her seventh studio album.

"I like to be free," she explained on The Ellen DeGeneres Show Dec. 7. "Sometimes, the less clothing, the better! I'm just comfortable in my skin and my body."

She then joked of her talk show outfit, "Had I had this beautiful sweater . . . I would have worn that on the cover of Lotus."

Host Ellen DeGeneres also asked the "Your Body" singer about her Oct. 3 meeting with U.S. Secretary of State Hillary Clinton. (Aguilera was given the McGovern Award for her quest to fight global hunger.) "Let's talk about this next picture of Hillary checking you out," the 54-year-old laughed.

"That looks like it was Photoshopped but it's not. It was a real moment," said Aguilera, who celebrates her 32nd birthday Dec. 18.

"Could you feel her gazing down on your 'breasteses?'" DeGeneres asked.

"She's such a force in a room. She's got that star charisma and everything about her. I couldn't take my eyes off her, either, so it was mutual," the Voice mentor responded. "Is that bad? I don't know. Maybe I shouldn't say that! I'm so inappropriate."