The singer was responsible for a backlash against Barack and his wife, Michelle, after sharing unauthorised photos from the event.
Grammy Award-winning singer Badu, 50, shared a photo of the couple dancing around hundreds of guests without wearing masks.
After Badu – real name Erica Wright – posted the now-deleted images online, the Obamas received criticism online, with many using the hashtagged phrase “ObamaVariant”. Others called it a “superspreader event”.
Badu has now issued an apology to the couple.
“Mr And Mrs Obama, Please forgive me 4 being the ‘terrible guest’ at such a sacred event for your family,” she wrote, telling her followers she removed the footage as it was the “right thing” to do.
“I was so inconsiderate,’ she added. “Thank you for all your love. What an example of ‘how NOT’ to be.”
The singer attended the luau-themed party at Martha’s Vineyard on 7 August, with her boyfriend JaRon Adkison.
She was fortunate to be included on the invite list following news that the Obamas had to cut the party’s capacity from 475 to 200 due to Covid regulations.
His spokesperson Hanna Hankins said was due to “the new spread of the Delta variant over the past week”, adding that Obama is “appreciative of others sending their birthday wishes from afar and looks forward to seeing people soon”.
According to The New York Times, Curb Your Enthusiasm star Larry David and TV hosts David Letterman and Conan O’Brien were uninvited from the party.