Kimberly Guilfoyle, the girlfriend of President Donald Trump's oldest son Donald Trump Jr. and a fundraiser for the Trump campaign, has tested positive for coronavirus, according to the chief of staff of the committee she leads.

"After testing positive, Kimberly was immediately isolated to limit any exposure," said Sergio Gor, chief of staff for the Trump Victory Finance Committee.

"She's doing well, and will be retested to ensure the diagnosis is correct since she's asymptomatic but as a precaution will cancel all upcoming events. Donald Trump Jr. was tested negative, but as a precaution is also self-isolating and is cancelling all public events."

Kimberly Guilfoyle with the Trumps
Donald Trump Jr. (left), Donald Trump and Kimberly Guilfoyle. Twitter / Kimberly Guilfoyle

Trump's Tulsa Rally a Hotbed for COVID-19?

Although Guilfoyle did not come into recent contact with the President, she was present backstage at his rally in Tulsa, Oklahoma last month and also attended his event in Phoenix, Arizona. Guilfoyle isn't the first person who attended the Tulsa rally to test positive for COVID-19.

On Thursday, a spokesman for Herman Cain, a Republican politician and 2011 primary candidate for the party's presidential nominee, announced that Cain had developed "serious symptoms" of coronavirus and was hospitalized after testing positive for the disease. He had also attended Trump's rally in Tulsa on June 20.

Donald Trump Rally
Twitter / Donald Trump

Video footage showed Cain seated in close proximity with other supporters in the crowd without a mask on. Additionally, eight Trump advance team staffers who were in Tulsa tested positive for coronavirus and eight other Secret Service agents who were at the event have also been diagnosed with the virus.

The agents, who were assigned Vice President Mike Pence's detail ahead of his visit to Arizona, have been forced to quarantine in a hotel in Phoenix, prompting the Vice President to postpone his visit by a day.

Trump's 4th of July Event at Mt. Rushmore

Guilfoyle's positive diagnosis came in South Dakota, where she and Trump Jr. were holding fundraisers for Trump's re-election. She was set to attend the President's event at Mount Rushmore, according to a source familiar with the matter.

As the U.S. set another record in newly reported coronavirus cases on Friday, thousands gathered for Trump's 4th of July celebrations at the famous landmark, many without protective face coverings or masks. Nor was there any evidence of social distancing in the tightly packed crowds assembled for Trump's speech and fireworks display.