Hannah Hankins, a spokeswoman for the former president, said in a statement obtained by Fox News that the "outdoor event was planned months ago in accordance with all public health guidelines and with covid safeguards in place."
"Due to the new spread of the delta variant over the past week, the President and Mrs. Obama have decided to significantly scale back the event to include only family and close friends. President Obama is appreciative of others sending their birthday wishes from afar and looks forward to seeing people soon."
Obama’s birthday is Wednesday but the party had been scheduled for this coming Saturday.
News of the birthday party – which will reportedly include 475 of the former president’s closest guests – drew the ire of critics on social media, who characterized the move as hypocritical in light of the new guidance on the delta variant.
Sources previously told The Hill that the guest list included Oprah Winfrey and George Clooney.
Prior to the cancelation, plans were for guests to be tested for the coronavirus and to be admitted only if they were already vaccinated, according to reports.
But the former president faced criticism that the party might become a "super spreader" event.
Fox News' Julius Young contributed to this report
This is a developing story. Check back for updates.