The surest sign of an epic house party? Double-check the footwear on the way out.

If the stiletto set has switched to flats (or just given up on shoes altogether), then a good time was had. And so it was at the White House recently.

On Friday, President Obama and first lady Michelle Obama hosted their final musical event at the White House, a concert in conjunction with BET entitled “Love and Happiness.” No, the president didn’t sing any Al Green. Not even a little.

According to the lucky ones in the audience, the evening featuring performances by Bell Biv DeVoe, Jill Scott and Janelle Monae was both surreal and downright normal (if you were at a club).

“It was a very special night,” said one guest still recovering from the concert and after-party that stretched until the wee hours of Saturday morning. “I thought I dreamed this.”

Upon arrival, the 300 or more guests, including supermodel Naomi Campbell, comedian Dave Chappelle and actor Bradley Cooper, surrendered their cellphones — a common practice when the Obamas want to really cut loose. The crowd was then shuttled to the South Lawn, where the Italian state dinner had been held just days before, for a two-hour concert by the Obamas’ favorite musicians and appreciations by pals such as Samuel L. Jackson.

From center stage, Obama explained at the start of the concert that the People’s House should “reflect the amazing diversity, and the imagination and the incredible ingenuity that defines the American people.”

“And while much of the music that you will hear this evening — gospel, R&B, rap — is rooted in the African American experience, it’s not just black music. This is an essential part of the American experience. It’s a mirror to who we are, and a reminder of who we can be.”

At about 10 p.m., attendees headed to the East Room for the after-party starring DJ D-Nice. And that is when things really got loose. According to one source, folks tried to “look cute” while the legendary DJ spun old- and new-school hits but “that ended quickly.” By this point in the night the president was sans jacket and tie, with his shirt sleeves rolled up dancing with abandon to Drake’s “Hotline Bling.”

The commander in chief had warned everyone earlier that there would be “no twerking” — at least by the president. He couldn’t account for Usher. And hey, isn’t that Donna Brazile, the interim chair of the Democratic National Committee, in the middle of a dance circle? Yep.

“You could see that the Obamas felt very comfortable,” said our source. “They were with their people — and I don’t mean African Americans — people who’d supported them and held them up and allowed them to do what they do. It was a really special night.”

The concert will premiere Nov. 15 at 9 p.m. on BET.