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Justin Timberlake had quite a few celebrity fans in the audience for his concert at Brooklyn's Barclays Center over the weekend, as part of his "The 20/20 Experience" Tour. 

Taylor Swift, Beyonce, and HAIM all came out to watch Justin's show, and danced like crazy when Jay Z joined him on stage to perform "Holy Grail."

One fan caught them all on Instagram singing and dancing along:

#JustinTimberlake #TaylorSwift #Beyonce #JZ @justintimberlake @taylorswift @beyonce @ambergaleo @_dino_mike_

A video posted by Zoa Chasin (@zchasin) on

Justin's wife Jessica Biel, who is rumored to be pregnant with their first child together, was also in attendance to watch her hubby do his thing on stage.

Dance along with Taylor, Beyonce, HAIM and Jessica Biel,  and watch Justin and Jay perform "Holy Grail" at his star-studded concert below!

Jay Z, Beyonce, Justin Timberlake, and HAIM were also all at Taylor Swift's birthday bash on Friday night after the iHeartRadio Jingle Ball hosted by Z100, along with Sam Smith, Nick Jonas, Selena Gomez and more. 

So this is being 25..... #WHAT #bestbirthdayEVER

A photo posted by Taylor Swift (@taylorswift) on

When you're making a wish, but you already have all you really need standing around you.

A photo posted by Taylor Swift (@taylorswift) on

It looks like Taylor Swift had the BEST 25th birthday weekend EVER!

Photos: Splash News & Getty Images