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Katy Perry's Britney Spears-inspired VMA outfit earned her high marks from Spears, herself.

After Perry turned up on the red carpet Sunday in the custom denim Versace, she tweeted, "I did my best impression, hope u likey!"

Spears, who was performing in Las Vegas Sunday night, tweeted back: "Just when I thought the denim dress had retired….you bring it back! You looked amazing tonight bb."

. @katyperry Just when I thought the denim dress had retired….you bring it back! You looked amazing tonight bb ;)

- Britney Spears (@britneyspears) August 25, 2014

Perry found the inspiration for her outfit Friday after exchanging tweets with the "Toxic" singer.

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When Spears posted her best Woody Woodpecker impression on Instagram, Perry responded, "This is the best thing I've seen all day bb."

Spears replied with a challenge to Perry: "@katyperry You're up next. #Noexcuses. You have 24 hours to do your best impression."

Perry accepted and promised Spears, "I'll show u my best impression on the red carpet at the VMA's tomorrow… Wait for it bb."

Just before walking the carpet, Perry dropped another hint about her dress. "I must admit my outfit is a result of my love for nostalgia and my tumblr addiction," she tweeted.

Not only did Perry channel Spears, she showed up with her recent collaborator, rapper Riff Raff, in matching custom Versace.

Together, they brought back memories of when Spears and then-boyfriend Justin Timberlake wore the same style outfits at the 28th Annual American Music Awards in 2001.