Katy Perry Calls Madonna 'Mom' Onstage And Then Proceeds To Shake Her Butt

And then they drink out of a banana flask.

Hello, and thank you for tuning into another installment of "Stars Are Just Like Us." Today's episode features Katy Perry, who pulled out her inner fangirl when Madonna brought her onstage.

Madonna invited KP onstage to dance at her Rebel Heart Tour at The Forum in Inglewood, California on Tuesday night. Together, they performed "Unapologetic Bitch" and twerked around, dipping their butts low and whatnot. Madge treated Perry like a fan, asking her for her name and giving her a special gift -- a banana flask -- "I'm sure you can find other things to do with this," she said.

"Bye, bye, Katheryn," Madonna said, leaving the stage.

Later that night, KP Instagrammed the insanity, highlighting the moment when she got so starstruck she called Madonna "mom" onstage. "Mom," of course, is the term used by superfans to describe their pop-star idols.

"Because all popstars are code 'mom' #meta," Katy wrote in Instagram. She also shared more video of their booty fest, saying, "Well, that was unrehearsed but ?? ILY @madonna my ?QUEEN?"

Watch the whole thing go down: