Prom Has Changed A Lot Since You Went. Lily Rose Depp Is Proof.

While you're looking back at prom photos thinking, "What was I thinking?" like Rachel and Monica from "Friends," Lily-Rose Depp attended her prom in a timeless gown more fit for an awards show than a high school dance.

Depp attended prom in Los Angeles on Sunday alongside Harley Quinn Smith, the daughter of director Kevin Smith, with whom she co-stars in his new movie "Yoga Hosers." The doting dad was on hand for pre-prom festivities and, lucky for us, he shared a photo of the two lovely ladies all dressed up and ready to go:

Quinn looked a little more like a teenager in a sleeveless black gown that gathered in front, which she wore with a gold clutch. Depp, who left her hoodie at home but brought her keen modeling chops, wore a nude slip dress that appeared to be crushed velvet.

The one giveaway that this was prom and not a big Hollywood event? Depp dutifully held her cell phone in her hand. "All the better to snapchat with," she probably thought.

Kind of puts your big, pouffy gown to shame, eh?