Madonna Spanks Katy Perry During Her Star-Studded Concert in L.A.

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Taylor Swift isn't the only one with famous fans.

On Tuesday night, Madonna took over The Forum in Los Angeles, California as part of her Rebel Heart tour, and Ashton Kutcher, Mila Kunis, Queen Latifah, Fergie and Salma Hayek were spotted at the show.

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Photo by: Joseph Ferrugio

However, one lucky star was invited up on stage. Swift's frenemy, Katy Perry, was summoned to join Madonna for a toast during the concert. An ET eyewitness saw the pop star seated next to Kunis and Kutcher before she hit the stage, and afterwards spotted her pal, designer Jeremy Scott. 

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The 31-year-old pop star grimaced as she sipped out of the 57-year-old singer's banana-shaped flask.

"Sharing a Banana with Katy Perry!! Highlight of my show at the Forum!" Madonna Instagrammed to her 4.9 million followers.

The drink appeared to loosen Perry up as she later grinded up on the music icon while on stage. "Best Unapologetic b**ch ever!" Madonna wrote. "Thank you Katy! Thank you L.A."

Perry also shared some videos from her Rebel Heart dance party. "Well, that was unrehearsed but @madonna [is] my QUEEN," she Instagrammed.

The "Roar" singer even got spanked by Madonna.

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Perry also explained why she referred to Madonna as "mom" during the concert, quipping, "Because all pop stars are code 'mom.'"

While it's clear that these two are pals, Madonna also doesn't appear to have any bad blood towards Swift. In an interview with Rolling Stone magazine earlier this year, she even compared herself to the "Shake It Off" singer.

WATCH: Beyonce, Katy Perry and Nicki Minaj Declare 'B**ch I'm Madonna' in Star-Studded New Video

“She has an opinion, and she's going against the norm," Madonna told the mag. "So in that respect, she is similar to me, yeah. And also, people just want to give her a hard time all the time because they think she's a goody-two-shoes, so of course I want to embrace her."

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