The 18-year-old actress, who graduated from Campbell Hall High School earlier this month, revealed that while her prom experience was spent thousands of miles away from the official school event, it was still the best night she could have hoped for.
With her film, The Neon Demon, in theaters now, Fanning opted to attend the Cannes Film Festival over the ballroom where her peers would be partying. She and her best friend, Cass, rubbed shoulders with some of the biggest names in Hollywood.
"Cass is my best friend in the entire world," Fanning explained. "We always planned to go our senior year to prom together, but then I had to call him and I was like, 'I'm going to Cannes' and then we were like, 'Wait, do you want to come out to Cannes?!' He was like, 'Yes!'"
Classmate Ariel Winter did make the prom, and since they graduated in the same class, Fanning entertained the idea of collaborating with the Modern Family star someday.
"That would be fun!" she said. "We're very good friends."
With high school being a thing of the past, Fanning is looking at what's next in her future.
"For now I think I'm just going to wait a year and just figure things out," she said. "It's a very exciting time this whole year. Lots of things have happened with The Neon Demon coming out and turning 18."
In The Neon Demon, Fanning plays aspiring model Jesse, who moves to Los Angeles and falls into a group of beauty-obsessed women who will do anything to get what she has.