With a Grace Kelly-esque updo, Mrs. O turned up her glamour quotient by accessorizing with three sparkly brooches (pinned to the frock's neckline), gold hoop earrings and a stack of gold bangles.
She was joined at the ceremony by Oprah Winfrey --we can't think of better representatives for the Windy City!
But despite Mrs. O and her golden glow, it wasn't meant to be for Chicago and the Olympics.
It was announced today that the 2016 games will be held in Rio de Janeiro or Madrid, but kicking Chicago out of the running "was one of the most shocking defeats ever handed down by the International Olympic Committee," reports Associated Press.
UPDATE 1:02pm: Rio de Janeiro is the official host of the 2016 Olympic games. Better practice that samba!
To get back in the spirit, check out Michelle Obama's winning looks in the below gallery.
Peter Macdiarmid, Getty Images
Charles Dharapak, Pool/Getty Images
Charles Dharapak, AFP / Getty Images
Charles Dharapak, Pool / AP
Michael Tercha, MCT
Nicholas Kamm, AFP/Getty Images
Jewel Samad, AFP/Getty Images
John Moore, Getty Images
JIM WATSON/AFP/Getty Images
U.S Department of State, flickr
Want more First Lady style? Michelle Obama clearly has black-tie dressing down, but she knows how to do casual, too.