Serene Jennifer Lopez Wows in Polished Ensemble at Charity Press Conference

Just days after giving a heartfelt performance that ended in tears at her Mohegan Sun concert in Montville, Conn. Saturday, Jennifer Lopez put on a brave face and stepped out for a charity press conference in West Los Angeles on Tuesday.

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With her hair twisted into a high "fun bun" (Lauren Conrad's fave hairstyle), Lopez switched directions from her sexy, sequin-adorned bodysuits and wore a polished, sophisticated sky blue Lisa Ho cocktail gown with criss-cross detail on the chest.

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She was accompanied by her younger sister, Lynda Lopez, to support the Maribel Foundation, a non-profit organization the star formed in 2009 to improve healthcare for women and children in need.

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The "On the Floor" singer announced the foundation's partnership with Samsung and Best Buy, who have pledged to donate up to $500,000 to the cause from the sales of select Samsung products.