"I want to share that I have tested positive for COVID-19," tweeted Ewing, who's in his third season as head coach at Georgetown University, his alma mater.
"This virus is serious and should not be taken lightly," he added. "I want to encourage everyone to stay safe and take care of yourselves and your loved ones."
Ewing, 57, has been isolated at a Washington, D.C. hospital, according to the school.
"I went to war with you for ten years," fellow former Knick Charles Oakley tweeted. "I won’t leave you on the battlefield now. Get well Patrick. More fights ahead."
Born in Kingston, Jamaica, Patrick Aloysius Ewing played 17 seasons for three teams in the NBA -- 15 of those for the New York Knicks, with whom he went to the finals twice, losing in 1994 to the Houston Rockets and 1998 to the San Antonio Spurs.
The 7-foot center was the NBA's Rookie of the Year in 1986, an 11-time NBA All-Star and a member of the original 1992 Olympic "Dream Team," which, along with Michael Jordan, Magic Johnson and Larry Bird became known as the greatest basketball team ever assembled.
Ewing was also the NCAA Final Four Most Outstanding Player in 1984, when he led the Hoyas to the national championship.
The Knicks made him the first selection in the first-ever NBA draft lottery in May 1985.
Ewing was inducted into the James Naismith Memorial Basketball Hall of Fame in 2008. The Knickerbockers also retired his number 33.
Ewing sold his Cresskill mansion on Vaccaro Drive for $2.65 million two months ago.
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