Photos of the Week: Katy Perry, Nick Jonas, Lil Mama
Singer Katy Perry performs during the ski winter opening on November 28, 2009 in Ischgl, Austria. Getty Images

Katy Perry helped fans in Austria get into the holiday spirit, while Lil Mama helped feed the less fortunate in New York. Nick Jonas went solo at the Grammy nominations concert, Ashlee Simpson made her Broadway debut and Stevie Wonder got props from the U.N. It all happened this week, and we've got the pics to prove it.

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