CHICAGO: Speculation was rife online about who would be the much vaunted special guest Thursday on the Democratic National Convention's final night, with figures from Beyonce to George W. Bush in the frame.

Beyonce was the name lighting up social media ahead of Vice President Kamala Harris's primetime address.

Celebrity gossip site TMZ fueled the fire with an all caps headline on its homepage screaming "performing at DNC's final night!!!" above a picture of the megastar.

Taylor Swift was also one of the names circulating in media and political circles, with celebrity watchers trying to ascertain the whereabout of private jets the pop icon has previously used.

Former Republican presidential nominee Mitt Romney, currently a US senator who has criticized former president Donald Trump, was even moved to deny it would be him.

"Contrary to fake news posts, I am not the surprise guest at the DNC tonight. My guess is that it will be Beyoncé or Taylor Swift," Romney posted on X. "So disappointing, I know!"

His fellow Republican George W. Bush was put forward as a contender for the surprise spot, with "Republicans against Trump" posting a picture of Bush embracing then first lady Michelle Obama to the account's 765,000 followers on X.

One wag suggested it would be the divisive Raygun, whose breakdancing efforts at the Paris Olympics spawned a plethora of mocking memes.

The Democratic convention's organisers have been tight-lipped about the identity of the special guest.