"You're up next. #noexcuses. You have 24 hours to do your best impression," Spears tweeted to the "Dark Horse" singer on Saturday.
"I'll show u my best impression on the red carpet at the VMA's tomorrow... Wait for it bb," Perry replied.
Oh, and she delivered.
The dark-haired singer showed up on the red carpet on Vine star Riff Raff's arm — and they were both clad in custom Versace patchwork denim, a la the look Britney Spears and Justin Timberlake wore to the 2001 American Music Awards.
And it was on. point.
"This is how we do the remix," Perry said on the red carpet, though we're disappointed Riff Raff didn't add the infamous denim cowboy hat that Timberlake rocked back in the day.
We're pretty sure Spears appreciates the dress, especially since rumor has it she still has the famous dress stuffed somewhere in her archives.
"Well, I don't think it's something you can repeat, what you've done in the past," Spears told MTV News in 2013 of the iconic look. "You always have to bring the new, something new and fresh and that's what I did. Everything is really different and elaborated, and it's very intricate and different."
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