Credit: CBS/John Paul Filo/Landov

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.

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.

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.

"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."