The Girls Next Door star suits up in her two-piece to lead the world's largest bikini parade in Las Vegas. Plus: Gretchen & Slade, Ellen Pompeo, Pete & Ashlee and more

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RED ALERT

She's lighting up New York City! Hilary Duff prepares to set a model of the Empire State Building aglow in red Thursday afternoon in honor of the 24th annual AIDS Walk New York (the real skyscraper turns red at dusk). The singer-actress is co-hosting the charity event's opening ceremony on Sunday, which benefits the Gay Men's Health Crisis.