President Obama: The Belieber in Chief!

Who knew President Barack Obama had a base case of Bieber Fever?

Sure enough, the commander in chief gave us a glimpse of his inner teenybopper as he grooved to Justin Bieber during the Christmas in Washington concert at the National Building Museum on Sunday.

The annual event, which also featured performances by Cee Lo Green, Jennifer Hudson and The Band Perry, was hosted by Conan O'Brien, who told the crowd that the holidays serve as a reminder of the miracle child worshiped by millions

MORE: Kermit the Frog Leaps Over to D.C. for White House Christmas Tree Lighting

"I'm speaking of course, of Justin Bieber," joked the talk show host as he introduced the heartthrob, who took the stage to sing "Away in a Manger."

In addition to the president, the show was also attended by his wife, Michelle, and the couple's two daughters, Sasha and Malia. During the concert, O'Brien playfully took a swipe at the first lady's "Let's Move" health campaign.

"It's not easy to be a child at the White House these days," he pointed out. "Santa's probably not going to stop at a house that leaves out a cup of organic soy milk and a plate of celery cookies."

Prior to the big show, which benefited the Children's National Medical Center, the Obamas met with several of the hospital's young patients, who were dressed as elves.

Scarlett Johansson Tells Cosmopolitan About her Personal Life

Scarlett Johansson never tells much about her personal life but for Cosmopolitan she opened up a bit and now we know all about why the actress married Ryan Reynolds and why it didn’t work, what lesson she’s learned and what it feels like for her to be alone now.

Scarlett Johansson looks fabulous on the cover of Cosmopolitan January 2012 issue. The actress, who has divorced from Ryan Reynolds this year, wears a sexy purple dress by OMO Norma Kamali on the front page.

Scarlett, who looks really tanned on the cover of Cosmopolitan January 2012 edition, gives a candid interview about her personal life. She talks about her attraction to bad boys, on how difficult relationships are, and what it feels like being along.

Read the highlights from Scarlett Johansson’s interview for Cosmopolitan January 2012:

Scarlett Johansson on playing roles based on her looks: “As a 19-year-old girl, I was eager to play into that. Why not? You’re 19 and you’re feeling fabulous and young. I don’t know that I could have sold myself as a character actor at 19.”

Scarlett Johansson on attraction to bad boys: “I’m attracted to the quality of being adventurous and perhaps a bit mischievous and also questioning authority and being proactive. If that makes up a quintessential bad boy, then whatever. I’m not at all attracted to meanness or bullying, but I do think conviction is attractive. I mean, really, who doesn’t?”

Scarlett Johansson on getting married to Ryan Reynolds: “I’m a big believer that when something feels right, you should do it. I’m a big believer in instinct. Getting married was the right thing to do because it was natural. It grew out of a romance and love and a desire to have a future with somebody, and I was very fortunate that I married somebody who turned out to be the person I thought he would be.”

Scarlett Johansson on how complicated a marriage can be: “Relationships are complicated and being married is a living, breathing process. I think I was not fully aware of the peaks and the valleys. I wasn’t prepared to hunker down and do the work

Scarlett Johansson on the lesson she’s learned: “You have to be very confident an dsolid within yourself to have a successful marriage.”

Scarlett Johansson on how she feels being alone: “It’s strange. I’ve never been single for a chunk of time before. You miss having a partner and a confidant, but I have to say, I’m appreciating having the time to get to know myself.”

Kylie & Kendall Jenner to Pippa Middleton: Kid Sisters Having Best Year Ever!

The year is coming to a close, and looking back, we realize that 2011 was the year of the celebrity kid sisters! Whether they were involved in scandal or showing off their talent, we could hardly go through a day this year without hearing about a pair of celeb sisters – and we loved it!

Lindsay Lohan stayed in the headlines all year, thanks to her court-ordered house arrest  and her recent stint with Playboy, and her younger sister Ali, 18, has been swarmed with plastic surgery rumors (that she, of course denies).

Thanks to her fairytale Royal Wedding to Prince William, Kate Middleton became one of the most envied women in the world, and her socialite sister Pippa, 28, has transformed into quite the fashion icon herself!