Within minutes of the news breaking, celebrities took to Twitter to react to his diagnosis. Actress and activist Alyssa Milano, who previously opened up about her battle with COVID-19, offered sympathy.
"As someone who has had #COVID19 and still suffers from post-covid syndrome, I can honestly say with all that I am that I wouldn’t wish this virus on my worst enemy. Please wear a mask," she wrote on Twitter.
Milano then reiterated her support for Biden in the upcoming November election by retweeting musician Ben Lee, who wrote, "Joe Biden has a well thought out plan for leadership during Covid."
Trump said he and his wife are under quarantine in the White House. "Tonight, @FLOTUS and I tested positive for COVID-19. We will begin our quarantine and recovery process immediately. We will get through this TOGETHER!" he tweeted.
The first lady said in her own tweet, "As too many Americans have done this year, @potus & I are quarantining at home after testing positive for COVID-19. We are feeling good & I have postponed all upcoming engagements. Please be sure you are staying safe & we will all get through this together."
Dr. Sean P. Conley, the president’s physician, also confirmed Trump's and the first lady’s diagnoses.
“This evening I received confirmation that both President Trump and First Lady Melania Trump have tested positive for the SARS-coV-2- virus,” Conley said. “The President and First Lady are both well at this time, and they plan to remain at home within the White House during their convalescence.”
Trump contracted the virus after one of his top aides, Hope Hicks, tested positive on Thursday. Hicks traveled with him aboard Air Force One to Tuesday night’s debate and to his rally in Minnesota the following day.
Milano first revealed she tested positive for the coronavirus in August. She has since provided updates on her health, noting that she is still suffering from lingering effects. She told fans on social media she's had heart palpitations, hair loss and forgetfulness months after she first experienced symptoms.
Although Milano's latest CT scan of her lungs and cardiac MRI came back “normal," the "Charmed" alum revealed she is still experiencing “vertigo, stomach abnormalities, irregular periods, heart palpitations, shortness of breath, zero short term memory, and general malaise.”
"Everything hurt. Loss of smell. It felt like an elephant was sitting on my chest. I couldn’t breathe. I couldn’t keep food in me. I lost 9 pounds in 2 weeks," she wrote on Instagram. "I was confused. Low grade fever. And the headaches were horrible."
"This virus sucks. Please take it seriously," Milano concluded.
Fox News' Brooke Stigman and Nate Day contributed to this report.