The First Lady, 48, stunned in a vibrant cobalt blue sheath from Barbara Tfank's resort collection, which reportedly retails for approximately $2,400.
This is Obama's second time wearing a look by the designer. Last year she chose a pale green brocade dress with a pink cropped jacket for a visit with Prince William and Duchess Kate in the U.K. last year.
"For me fashion is fun, and it's supposed to help you feel good about yourself," the first lady told Women's Health back in 2009. "I think that's what all women should focus on: what makes them happy and feel comfortable and beautiful. I wear what I love. Sometimes people like it, sometimes they don't. I'm fine with that."