It's Tay vs. Tom time! Unexpected pals Taylor Swift and Tom Hiddleston had an incredible dance-off at the Metropolitan Museum of Art's Costume Institute Gala in NYC, on Monday, May 2, and there's video proof.

Swift, 26, and the Avengers actor, 35, bonded throughout the soiree and even arrived together at the official Met Gala afterparty at Boom Boom Room at the Standard Hotel in downtown Manhattan shortly after midnight. An inside observer tells Us Weekly that the twosome stuck together all night and appeared to be really good friends.

In fact, an unearthed Instagram video shows the pair jamming (inside the Metropolitan Museum of Art!) to T.I.'s smash 2004 hit "Bring Em Out."

TAYLOR SWIFT & TOM HIDDLESTON GETTING DOWN #MET #DANCE #FUNFUN #PRINCE #NYC #tomhiddleston

A video posted by Carlos Souza (@carlossouza1311) on

The mesmerizing video posted by jeweler and Valentino brand ambassador Carlos Souza opens with the pair bumping along to the beat-heavy opening of the song. Swift twirls and shimmies while Hiddleston breaks it down on the floor. Both bust out their best moves as they draw a crowd. 

Another video of the two dancing was also featured on the Met's Snapchat channel on Monday night. 

The dancing didn't stop there. The buds continued to move their way into the night at the Met Gala afterparty, where an observer says they were joined on the floor by Sienna Miller.

Twirling partner Hiddleston also helped Swift put on her combat boots when she was ready to kick off her strappy Louis Vuitton stilettos.

"Tom had to stand up and bang on the bottom of the shoe to get it on," the same observer tells Us Weekly. "Tom got the shoe on Taylor's foot and she laughed."

Watch their dance-off above!

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