President Barack Obama and family had a long day on Monday with all the inaugural functions and formalities. One would think that the appearances and the mingling would tire the First Family out and given the chance they would end their night early.

However, that was not the case with this ultra-cool President. President Obama and First Lady Michelle Obama hosted a private star-studded after-party Monday night in the East Wing of the White House. Sources confirmed to various media people that the party, which had a dinner and dessert buffet spread, went on till the wee hours of Tuesday morning.

Many celebrities who attended the party that began at 9 p.m. Monday tweeted about how cool the President and his wife are and what a splendid house party it was.

The Obamas, including their daughters Malia and Sasha, entered the party at around 10 p.m. and let their hair down and enjoyed themselves like any other family.

People Magazine reported that around 300 guests were invited for the party including top-notch politicians and celebrities from the entertainment industry. Guests included former president Bill Clinton, John Kerry and Colin Powell.

Alicia Keys and husband Swizz Beatz, Jennifer Hudson, Kelly Clarkson and fiancé Brandon Blackstone, Eva Longoria, Kerry Washington, Usher, John Legend and fiancée Chrissy Teigen, Katy Perry and John Mayer were few of the celebrities that were lucky enough to land an invitation to this extremely-private do.

Click here to see pictures from inside the party.

DJ Cassidy took on the responsibility to spin out tunes that would pull people onto the dance floor. Eric Benet, Janelle Monae and Ledisi gave live performances which upped the tempo of the party.

Usher, Keys, Hudson and Perry took the stage to sing along when DJ Cassidy played their tunes.

Many guests left while the party was on in full swing. President Obama was spotted hugging and mingling with guests looking casual without his coat and tie while Michelle, still wearing her red Jason Wu gown, was dancing to Beyonce's "Single Ladies" with other guests.

The Hollywood Reporter also published that President Obama and Usher had a dance off to the hit song "Gangnam Style" which is sung by popular Korean popstar Psy.

A source told Us Magazine that "The party went on until 2 a.m.!" and "They all stayed until the end... Obama was dancing with everyone and let his guard down!"

"California Girls" singer Perry tweeted after the party saying, "Just left the White House. All other parties from here on out will be judged unless they take place at the White House."

Clarkson, who performed earlier during the day at the inaugural functions also tweeted saying, "I kid you not, Michelle Obama stood up and got the party started ....seriously cool First Lady."

Teigen, model fiancée of Legend tweeted much later in the night, "I don't even know what to say. It's 3:15am and I just teared up seeing our president getting down at the white house."

The Obamas showed no signs of being tired when they were spotted fresh and bright the next morning at the Presidential Inaugural Prayer Service at the National Cathedral in Washington.