The newly engaged star shows off a diamond sparkler at the Met's Costume Institute Gala in N.Y.C. Plus: Mariah Carey, Ashton & Demi, Clive Owen and more

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POWER OF PINK

Reese Witherspoon hits the pavement for the Avon Walk for Breast Cancer in Washington, D.C., on Sunday. The actress, who's the global ambassador and honorary chair of the Avon Foundation, joined 3,500 walkers in the two-day event, which raised $8.1 million for breast cancer research.