A representative for the Bang Bang hitmaker reveals the singer was recently asked to join an unidentified soul legend for a duet to help close out the four-day political gathering, but she had to turn down the opportunity.

The DNC kicks off on Monday (25Jul16) and runs until Thursday (28Jul16), during which stars including Lady Gaga, Lenny Kravitz, and Snoop Dogg have all been booked to perform at various events.

Former Secretary of State and First Lady Hillary Clinton is expected to formally accept the Democratic Party members' nomination as president on Thursday.

The news of Ariana's prestigious invitation emerges two days after leaked documents from the Democratic National Committee suggested she had been passed over as a potential White House performer last year (15) over her doughnut-licking scandal.

The 23-year-old sparked controversy after she was caught on security cameras appearing to lick sugary treats she did not purchase at a bakery in California. The video also showed Ariana declaring, "I hate America" - and according to leaked emails between White House officials, the incidents were enough to strike the star from a list of possible acts for a gala with U.S. President Barack Obama in late 2015.