Nicolas Moore

Most people would agree, when it comes to sex appeal, Shakira has plenty.

But Shakira herself said there's one woman who trumps her: her new duet partner - Rihanna.

"Working with her was utopia. She's the sexiest woman on the planet," Shakira told Glamour for the cover story of the magazine's February issue.

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"At the end of the day, we're both just basically Caribbean girls. The chemistry was so good and so real. She taught me dance moves. She was a sweet teacher," the 36-year-old "Hips Don't Lie Singer" singer said.

Shakira and Rihanna's new collaboration, "Can't Remember to Forget," debuts January 13.

Of course, Shakira is famous for her own hip-shaking moves. But she's the first to say there's more to her life than that.

"I feel like I'm not on earth just to shake it and shake it endlessly, you know?" she told Glamour.

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Shakira discussed returning to NBC's "The Voice" as a coach next month, along with Usher.

"Dealing with boys at work and being the only girl can be challenging. I have my insecurities, but I've learned I have to be a good sport," she told Glamour. "I have to be able to take certain jokes and not take them personally…I had to develop a tough hide."

Shakira, whose son Milan will turn 1 on January 22, talked about her appearance, and whether her Latin fans have criticized her for dying her hair blonde, or not being curvy enough. "At the beginning," she reveals. "But my man Gerard [Piqué, Milan's father] prefers meat over bone. He doesn't like too skinny. That takes pressure off."

"I already have a lot to worry about," she continued. "This month I'm not exercising because I have an album to finish and I have a baby. And I like these pastries in front of me."