People yell as they see musicans Mindless Behavior as they attend the children's concert at the Washington Convention Center to celebrate military families on January 19, 2013 in Washington, DC. The U.S. capitol is preparing for the second inauguration of U.S. President Barack Obama, which will take place on January 21. (Photo by Joe Raedle/Getty Images)

WASHINGTON — Some 5,000 military kids, their parents, and local Washington D.C. school children packed into the Washington Convention Center Saturday night for the kids’ inaugural ball, the concert thrown by First Lady Michelle Obama and Dr. Jill Biden to honor the military families they support through their Joining Forces charity.

The event featured a parade of headlining performers, including Usher, Mindless Behavior, the cast of the hit TV show Glee and Katy Perry, who closed out the show

Between performances, the audience were treated to video greetings from a host of television and music stars, including the British group The Wanted, Ryan Seacrest, Django Unchained and Scandal star Kerry Washington, Jimmy Fallon, Ellen DeGeneres, and David Letterman. Other stars sending greetings to the military kids were Big Time Rush, Victoria Justice, Biz Markie and the cast of Yo Gabba Gabba.

The event was emceed by America’s Got Talent host Nick Cannon, who thanked the First Lady and Dr. Biden for their advocacy on behalf of military families, and for supporting his own charitable efforts.

Usher opened the show with a laser-filled performance of three of his biggest hits, throwing in a few partisan appeals to the crowd, ahead of President Barack Obama‘s second inaugural. Usher worked “Obama” into the lyrics for his hit song “Oh My Gosh” and during a pause in his playlist, asked the crowd, “Aren’t you guys excited that we’ve got another four years!?”

Usher wasn’t the only one to get a little political.

After a display by the giant Washington Nationals mascots, the “racing presidents,” Cannon declared the Abraham Lincoln giant costumed puppet the winner over Teddy Roosevelt, Thomas Jefferson and George Washington, adding: “honestly I think President Obama would have beat all of you.”

The show featured one of the groups Cannon’s show has helped make famous. Illuminate, a techno dance group that debuted on America’s Got Talent, performed a surreal dance number to “I’m Glad You Came.”

Dancing With the Stars winner J.R. Martinez, himself a military veteran who was severely burned on his face and body in Iraq, spoke to the crowd about the sacrifices of military families, particularly the children of service members. His presentation promoted “Joining Forces,” and he introduced a moving video that described the first and second ladies’ charity.