Britney celebrates Halloween in Las Vegas.

britney-spears-pom-oct31

Britney performed Piece Of Me on Halloween, but more importantly… re-posted a ~Britney & Justin Forever~ pic on Instagram.

For some reason, Britney opted out of dressing up this year for Halloween — leaving the fun up to her backup dancers who competed in a contest for best costume. The winner got their very own dedicated post on her social media accounts. Free promo!

Before we bombard you with videos from Saturday night, we need to take a moment of silence for Britney’s ode to her and Justin Timberlake’s iconic matching jean outfits at the 2001 American Music Awards. She re-posted this snap with the original poster’s hashtag #britneyandjustinforever (along with several other personalney moments):

#Repost @monicarosestyle ・・・ #britneyandjustinforever #FBF #AMAs #HappyHalloween ??? #britneyween

A photo posted by Britney Spears (@britneyspears) on


Before the show, Brit posted a few behind-the-scenes snaps of her and her dancers decked out in Halloween attire.

My team bringin’ on the #britneyween…

A photo posted by Britney Spears (@britneyspears) on

Shout out to @zacbrazenas who won the crew costume contest! #britneyween

A photo posted by Britney Spears (@britneyspears) on

Meet @mmatthewdarryl & @alex.jean… the #Britneyween costume winners! Happy Anniversary! You all look fantastic 🙂

A photo posted by Britney Spears (@britneyspears) on

My boys getting into a little Halloween mischief ?

A photo posted by Britney Spears (@britneyspears) on

This little girl is so adorable! She definitely knows how to celebrate #britneyween ??

A photo posted by Britney Spears (@britneyspears) on

Enjoy fan-footage from the show:

"Work *****" @britneyspears #lasvegas #planethollywood #halloween2015 #britneyhalloween #britneyspears #instaboy #instagay #instadaily #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Work *****" (sequence) @britneyspears #planethollywood #lasvegas #halloween2015 #itsbritneywitch #instaboy #instagay #instagay #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"womanizer" @britneyspears #lasvegas #planethollywood #halloween2015 #instaboy #instagay #instadaily #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"3" @britneyspears #lasvegas #itsbritneywitch #halloween2015 #britneyhalloween #instaboy #instagay #planethollywood #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"3" @britneyspears #itsbritneywitch #halloween2015 #britneyhalloween #planethollywood #lasvegas #instaboy #instagay #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Every time" @britneyspears #lasvegas #planethollywood #itsbritneywitch #britneyhalloween #britneyspears #instaboy #instagay #instadaily #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

???????????? "Baby one more time" @britneyspears #lasvegas #planethollywood #britneyhalloween #itsbritneywitch #instaboy #instagay #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Ops I did it again" @britneyspears #lasvegas #planethollywood #halloween2015 #itsbritneywitch #britneyhalloween #britneyspears #instaboy #instagay #instagay #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Ops I did it again" @britneyspears #lasvegas #planethollywood #halloween2015 #instaboy #instagay #instadaily #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Me against the music" @britneyspears #planethollywood #lasvegas #halloween2015 #instaboy #instagay #gay #ga#gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Pretty girls" ?????????? #heyprettygirls @britneyspears #instaboy #instagay #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Toxic" @britneyspears #lasvegas #planethollywood #instaboy #instagay #instadaily #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

My favorite song ?????????"Stronger" @britneyspears #lasvegas #planethollywood #instaboy #instagay #instagay #gayboy #gayguy #gayboy #halloween #halloween2015 #itsbritneywitch #britneyhalloween

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Drive me crazy" @britneyspears #lasvegas #planethollywood #halloween2015 #itsbritneywitch #gay #gayboy #gayguy #instaboy #instagay

A video posted by Alfonso Barrientos ? (@alfponcho) on

"You drive me crazy" @britneyspears #lasvegas #planethollywood #itsbritneywitch #halloween2015 #instagay #instamusic #instadaily #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

"Tilt the worlds end" @britneyspears #lasvegas #planethollywood #halloween2015 #itsbritneywitch #britneyhalloween #instagay #instaboy #instamusic #gay #gayboy #gayguy

A video posted by Alfonso Barrientos ? (@alfponcho) on

Britney waved at my camera! I DIED! #itsbritneybitch #happyhalloween #pieceofme @britneyspears #myqueen ? #britneyween

A video posted by Lauren Boehm (@loboehm) on

"Stronger" – Britney Spears #BritneySpears #BritneySpearsPieceofMe #LasVegas #life #love #fun #music #concert #happiness #joy #Halloween #HalloweeninVegas #HalloweenWeekend

A video posted by How You Do That There (@publicskool) on

"Circus" – Britney Spears #BritneySpears #BritneySpearsPieceofMe #life #love #happiness #joy #weekend #travel #concert #icon #Halloween #HalloweeninVegas #HalloweenWeekend

A video posted by How You Do That There (@publicskool) on

"Drive Me Crazy" – Britney Spears #BritneySpears #BritneySpearsPieceofMe #LasVegas #Vegas #life #love #joy #happiness #concert #icon #weekend #Saturday

A video posted by How You Do That There (@publicskool) on

I like this part. #hoo! #britney #pieceofme #vegas #breaktheice

A video posted by Wayne "Nickname" Farrens (@tellsanchito) on

#vegas #pieceofme #britneyween

A video posted by Chris O'Brien (@chris_tagram13) on

#vegas #pieceofme #britneyween

A video posted by Chris O'Brien (@chris_tagram13) on

#vegas #pieceofme #britneyween

A video posted by Chris O'Brien (@chris_tagram13) on

#vegas #pieceofme #britneyween

A video posted by Chris O'Brien (@chris_tagram13) on

"Baby One More Time" – Britney Spears #BritneySpears #BritneySpearsPieceofMe #LasVegas #Vegas #nightlife #night #weekend #Saturday #concert #life #love #happiness #joy #travel #Halloween #HalloweeninVegas #HalloweenWeekend #amazing #music

A video posted by How You Do That There (@publicskool) on

#BritneySpears #lasvegas #instagay #pieceofme @britneyspears

A video posted by George (@gossipboygg) on