Boston Celtics star Marcus Smart said he has the new coronavirus and urged young people to take the threat seriously and practice social distancing.

Smart tested positive Thursday but said he was not showing any of the symptoms.

"I feel great. I feel fine. I feel like I can go play a game right now," the 26-year-old from Texas told CNN Friday.

But he had a warning for young Americans like those shown partying on Florida beaches undeterred by the threat of COVID-19.

"I advise my generation, I am 26, to take it seriously," Smart said. "Be alert. Take precautions. By protecting yourself, you protect others.

"That's the key. People are not showing symptoms so it is hard for anyone to know they have the virus. But being around a group of people, friends, family and not isolating themselves, you are a carrier. You can spread the virus around without knowing."

On Twitter he also stressed that the younger generation must self-distance.

"This is not a joke. Not doing so is selfish. Together we can beat this, but we must beat it together by being apart for a short while. Much love!!," he tweeted.

At least 14 NBA team members have so far tested positive for COVID-19, including Brooklyn Nets Kevin Durant and Utah Jazz's Rudy Gobert and Donovan Mitchell.

Boston Celtics Marcus Smart urged young people to take the health threat seriously
Boston Celtics Marcus Smart urged young people to take the health threat seriously GETTY IMAGES NORTH AMERICA / Maddie Meyer

On Wednesday, commissioner Adam Silver said NBA players should be considered "super spreaders" of the disease.

Silver's comments came amid criticism that wealthy athletes were getting tested for the virus ahead of critically ill patients in US hospitals.

Smart said he was tested on Saturday and got the results five days later.

"I found out yesterday evening," he said. "I was like, Oh wow! It makes you alert to what is going on."

Smart told CNN he was not worried about his symptoms getting worse.

"I talked to my doctors and they just told me that I have not experienced symptoms yet so I should be on the last curve of the ball.

"I am just ready to get this behind and move on."

In 53 games in 2019-20, Smart is averaging 4.8 assists and 3.8 rebounds per contest.

Smart is a first-round pick of the Celtics in the 2014 NBA draft.