Stars Get in the Holiday Spirit

Rihanna posed in some sexy lingerie in front of the Christmas tree. The S&M singer captioned the festive Instagram pic on Dec. 23, 2013, writing: "@leleboo_phucku lingerie/pajama Christmas party #aftermath #goosehadmefeelinsometypeoway."

Dressed in her most festive red bikini and matching robe, Mariah Carey posed in front of her Christmas tree on Dec. 22, 2013, writing: "Warming up for the hottub moments!"

Sporting matching black bowler hats and coordinating red and green holiday sweaters, BFFs Ian McKellen and Patrick Stewart posed for this heartwarming photo with Santa. "Father Christmas!" Stewart tweeted.

Hilary Duff recently got festive with friends at the Switch Boutique Holiday Party on December 14 in Los Angeles, sporting ruby red lips and an adorable sparkly mini top hat.

The Hangover star Zach Galifianakis dressed up as Santa Claus for a special Comedy Bang Bang on IFC. WATCH.

Does she ever take off the high-heels?! Victoria Beckham gave plenty of her Instagram followers anxiety when she posted this pic of herself tottering on a ladder in stilettos, while putting the finishing touch on her pink Christmas tree. "Christmas can be dangerous fashion bunnies!" she wrote.

Victoria Justice proved you're never too old for Santa, spreading some holiday cheer at the Delta Air Lines' celebration of Holiday in the Hangar "Flight to the North Pole" for children of Children's Hospital Los Angeles and P.S. Arts on December 11 in Los Angeles.

What's on Rita Ora's wish list? Rita sent off her letter to Santa while celebrating the Material Girl holiday collection at Macy's on December 9 in New York City. 

Lady Gaga recently got into the holiday spirit as only she can, rocking a giant Christmas tree hat complete with a gold star out and about in London on December 8.

It's safe to say that Miley Cyrus is definitely getting on the naughty list this year! Miley Cyrus dressed in a racy holiday get-up and twerked on Santa at KIIS FM's Jingle Ball in Los Angeles on December 6.

Kelly Clarkson looked drop-dead gorgeous in this pretty red tulle Christmas dress. "Rockin' Christmas early with @parademagazine!" she tweeted.

"There's a Christmas tree in my hotel room and I'm really happy about it," Taylor Swift captioned this sweet photo on her Instagram.

The Mindy Project stars Mindy Kaling and Chris Messina posed together for an adorably festive snapshot. "Merry Christmas!" Kaling wrote on Instagram.

Ashley Tisdale snuggled up to Santa at Delta Air Lines and YMCA Of Greater New York's "Holiday Flight to The North Pole" event for PS 197 elementary school students in New York City on December 4.

President Barack Obama and first lady Michelle Obama held a Hanukkah reception at the Grand Foyer of the White House in Washington, D.C. on December 5.

Heidi Klum and her boyfriend Martin Kristen bought a whopping six Christmas trees with her children at Mr. Greentrees in Beverly Hills, Calif. on November 30.

Billy Ray Cyrus and Santa compared their enviable beards at the Hollywood Christmas Parade Benefiting Toys For Tots Foundation on December 1 in Hollywood, Calif.

Karina Smirnoff kept it cute in a quirky Santa hat also at the Hollywood Christmas Parade.

The Vampire Diaries star Kat Graham proved you're never too old to sit on Santa's lap at the Beverly Center Holiday debut with stars and their pets event in Los Angeles on November 14.

Also attending the Beverly Center Holiday debut event, Real Housewives star Lisa Vanderpump happily posed with Santa and her beloved dog Giggy in a show-stopping blue dress.