The English actor Idris Elba announced on Monday that he had tested positive for the coronavirus, sharing the news with fans in a video that he posted on Twitter.

“This morning I tested positive for Covid 19,” Mr. Elba wrote in a post that accompanied the video, referring to the disease caused by the coronavirus. “I feel ok, I have no symptoms so far but have been isolated since I found out about my possible exposure to the virus.”

Mr. Elba, 47, is best known for his roles in the HBO series “The Wire” and as the title character in the BBC police drama series “Luther.” He said he was tested “because I realized I was exposed to someone who had also tested positive.” He said he learned about that person’s positive test result on Friday. “I quarantined myself and got a test immediately,” Mr. Elba said.