Singer-songwriterChristopher Crosshas been diagnosed with the coronavirus. The five-time Grammy winner shared the news in alengthy Facebook postFriday. "I'm sorry to report that I am among the growing number of Americans who tested positive for the COVID-19 virus," he wrote. "Although I am fortunate enough to be cared for at home, this is possibly the worst illness I've ever had." The musician, whose songs "Arthur's Theme (Best That You Can Do)" and "Sailing" topped theBillboard Hot 100, urged his fans to take the growing global pandemic seriously.