President Obama and Michelle ObamaMichelle ObamaMelania Trump to lead US delegation to Invictus Games Michelle Obama opens up about racism she faced as first lady Video surfaces of Michelle Obama at Beyonce’s birthday party MORE shared a first dance Monday night to the same song that he famously crooned on the 2012 campaign trail: "Let's Stay Together."

The Al GreenAl GreenHouse Financial Services panel leaders spar over Trump, Russia Overnight Finance: Dems roll out 'Better Deal' economic agenda | Regulators mull changes to 'Volcker Rule' | Gingrich, small biz launch tax cut campaign House Dem seeks to prevent Trump from being able to pardon himself MORE classic was sung by Grammy and Academy Award winner Jennifer Hudson at both of the official inaugural balls.

During the presidential race, Obama sang a few lines of the tune's chorus at a fundraiser at New York's Apollo Theater.

While President Obama didn't address the crowd (or sing) at the inaugural ball, he did speak to military personnel at the Commander-in-Chiefs ball at the Washington Convention Center. "This party is just another way to say something we can never say enough of, 'Thank you,'" he said.

Michelle Obama dazzled in a red, custom-made Jason Wu chiffon and velvet gown. The couple smiled as thousands of supporters cheered and snapped photos.

They only stayed for one dance, waved to the crowd and moved on to the next event.

Later, Vice President Biden and Jill Biden, wearing a blue Vera Wang gown, danced to Jamie Foxx serenading them with "I Can't Stop Loving You."

Foxx teased Biden, saying "I understand you're a romantic man," before sitting down at the piano and breaking into song.

At the end of the dance, Biden went over to the piano to give Foxx a squeeze on the shoulders.

The sold-out inaugural ball featured a cash bar and snacks, including pretzels and Cheez-its.

Souvenirs were available for partygoers, ranging from a $3 Obama pencil to $45 for a pair of champagne flutes commemorating the inauguration.

Performers at the ball included Alicia Keys - who changed the lyrics of her hit song, "Girl on Fire," to "Obama's on fire" - the band fun., country music star Brad Paisley, Stevie Wonder, and Mexican rock group Mana.

Spotted among the packed crowd: Sen. Jeff FlakeJeff FlakeSenate ObamaCare repeal bill falls in shocking vote Passing the DACA legislation will provide relief to children living in fear OPINION | Healthcare vote a political death wish for GOP in 2018 MORE (R-Ariz.) and his wife, Sen. Sheldon WhitehouseSheldon WhitehouseDem senators 'seek assurances' Icahn not swaying regulators on AIG: report Overnight Regulation: Federal prisons want to increase use of restraints | EPA moves ahead on water rule repeal Overnight Energy: EPA moves forward with water rule repeal MORE (D-R.I.), and Rep. John BarrowJohn BarrowOur democracy can’t afford to cut legal aid services from the budget Dem files Ethics complaint on Benghazi panel Barrow thanks staff in farewell speech MORE (D-Ga.).