First up, the 22-year-old beauty stunned in this charcoal velvet gown with a dramatic ribbon detail designed by Guillaume Henry of Nina Ricci. He told The Cut he wanted Dakota to look "as light as the wind and as shiny as a rain of sequins" in the customized gown from his fall-winter 2016 show.
Meanwhile, her little sister proved she ain't so little anymore in this custom Thakoon ivory duchesse silk slip gown. The 18-year-old pulled her blonde locks in a tight Spice Girls-esque pony tail. Chic and simple!
We heard the two Fanning gals prepped for the big day together — so we're sure they planned to look as different as possible from each other!
Nicely done, ladies!
[Image via Getty Images.]