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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CHAIRMAN OF THE BALL

He's not having a ball – yet! George Clooney and girlfriend Sarah Larson (not pictured) arrive in New York on Sunday. The couple is expected to attend Monday night's Metropolitan Museum Costume Institute Gala, which the actor is co-chairing this year.