While many of today's brightest stars spent New Year's Eve 2013 performing live for all of their fans, others were busy partying and spending time with close friends.

Before he hit the stage for New Year's Rockin' Eve in L.A., Justin Bieber posed with his buddy Lil Twist and sipped on something bubbly, while One Direction member Harry Styles smooched his lady love Taylor Swift following her performance in Times Square. Like the lady in 'Red,' Kesha also performed on New Year's Eve 2013, and she later tweeted a picture of herself partying with those classic NYE shades.

Elsewhere, Rihanna and Chris Brown were up all night doing God know's what (but we have a hunch it began with "s" and ended with "x"), and Beyonce kept it classy with a New Year's Eve note and intimate performance for her fans in Vegas. Her hubby Jay-Z was performing in Brooklyn, and Big Time Rush member Kendall Schmidt took in the Jay-Z / Coldplay show from his seat at the Barclays Center. Meanwhile, Carlos Pena Jr. and his new girlfriend Alexa Vega spent the holiday in the Bahamas partying and bike riding with friends.

See more pics of pop stars celebrating New Year's Eve 2013, including Jennifer Lopez's fancy dinner party, Rita Ora's boozy, skydiving adventures in Dubai and Mariah Carey's Australian performance with her fam!

Justin Bieber + Lil Twist in L.A.

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Taylor Swift + Harry Styles in Times Square, N.Y.C. [WATCH THEM KISS]

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Kesha Celebrating After Performing at MTV's Club New Year's Eve

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Rihanna + Chris Brown in Bed Together

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Beyonce Performing Live in Las Vegas + a Note She Published

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Coldplay + Jay-Z Performing in Brooklyn, N.Y.

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Kendall Schmidt's View From the Jay-Z + Coldplay Show in Brooklyn

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Carlos Pena Jr., Alexa Vega + Friends Vacationing in the Bahamas

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Carly Rae Jepsen + M.C. Hammer in Times Square, N.Y.C.

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Psy, M.C. Hammer, Carly Rae Jepsen + Tyler Glenn of Neon Trees in Times Square, N.Y.C.

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Pitbull Performing in Times Square, N.Y.C.

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Jason Derulo + Jordin Sparks Celebrating Together

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Jennifer Lopez Prepping for Her New Year's Eve Dinner Party

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Rita Ora + Friends Partying and Skydiving in Dubai

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Ellie Goulding Celebrating in Dubai

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Calvin Harris Ringing in 2013 With Some Zebras

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Mariah Carey, Nick Cannon + Their Twins on Stage in Australia

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