On Monday night, she uploaded a video of herself inside her mansion, blasting and dancing to Eilish's song "Bad Guy. " Notably, the video also stars a stuffed snake, which Spears passionately swings over her shoulders and between her legs before abandoning it on the floor to pull out all of the stop for the grand finale, by sprawling across her piano.
But even in Spears's expansive catalogue of music video treatments, this one stands apart; the choreography happens to be the same that Spears showcased while performing her song "I'm a Slave 4 U" at the 2001 MTV VMAs.
Even Eilish's admission that she didn't believe the Spice Girls were real until 2017 didn't stop Julia Roberts from declaring that Eilish "is everything" in the weeks that followed.
Eilish, who was less than four months old at the time of Spears's original performance, may not have gotten the reference, but she—and 44,000 people who liked her comment (a simple "omg")—seemed to appreciate Spears's gesture all the same.
It's also been a safe space for millennials to ask a question of their own: "Who is Billie Eilish?
A video documenting her Duff-related ignorance was soon bombarded with replies from fans who seemed to take the remark as an "I don't know her"-level response.
Earlier this week, Billie Eilish posed a weighty question: "Who is Hillary Duff?
Related: Billie Eilish's Crusade to Make Millennials Feel Old Is Still Going Strong: "Who Is Hilary Duff?
One homemade Instagram video at a time. https://t.co/porF3xZXOM— W magazine (@wmag) June 6, 2019