“Promising Young Woman” director Emerald Fennell and stars Carey Mulligan and Bo Burnham stopped by Variety’s Sundance Studio to discuss the revenge thriller’s themes of “forgiveness, romance [and] Paris Hilton.”

Fennell says the film’s soundtrack, which includes music from Britney Spears and Paris Hilton, was intentionally taken very seriously.

“You often find this with pop music or popular culture — particularly pop culture that young women — like is treated ironically or it’s treated like a guilty pleasure,” Fennell said. “But I’ve always loved Britney Spears and I think ‘Toxic’ is one of the greatest songs ever written. The whole movie in general, I wanted to make sure these things we think of as silly and our culture dismisses like clothes, makeup, pop music, stuff that some women — not all women — enjoy, take it seriously.”

Mulligan added, “When Emerald and I met about the film, she sent me a playlist and ‘Toxic’ was on there twice. So it gave me an indication that Britney would be a big part of the film.”