She teared up a bit while talking about her late father, but Michelle Obama's outfit choice was absolutely flawless on The Late Show with David Letterman Monday Night.

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The First Lady, who's known for her impeccable, yet accessible style, chose a green, navy and white color-block Preen dress with on-trend peplum detail and belted waist for her first appearance on the late night talk show. She accessorized with a sparkling brooch, which complemented the stunning lines of the ensemble.

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In addition to chatting about Bo the first dog (whom she called "the smartest dog on the planet"), Obama, 48, told a funny story about a shopping trip to Target.

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"I thought I was undercover…no one knew that was me. Because a woman actually walked up to me. I was in the detergent aisle. She said, I kid you not, she said, 'Excuse me, I just have to ask you something…can you reach on that shelf and hand me the detergent?' I kid you not. And the only thing she said, 'Well you didn't have to make it look so easy.' That was my interaction. She had no idea who I was."

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