Jessica Simpson lookalike Katherine Heigl arrived on the red carpet for the premiere of her new movie 27 Dresses in early January 2008 wearing this very cute chignon.

The bun tied at the nape of her neck has a focal point at its center for a touch of old-fashioned formal hairstyling flair.

If you're thinking of an updo for prom that is something like this, one slight improvement would be to have the hair on the crown of your head a little lower or flatter than Katherine's. That will make it more closely follow the contour of your head.