Idris told that he thinks he caught the virus from another star on set [Photo: Idris Elba/Twitter]

Idris Elba says he reckons he knows who he caught coronavirus from.

The star recently filmed a video to let fans know that he had tested positive for COVID-19, despite not exhibiting any of the symptoms.

Today he shared a new post to update his followers - and finally answered why he had been tested if he had none of the symptoms.

"I was told that someone I had been in contact with had tested positive," Idris told, "I'm on location, about to start filming and the news breaks that this person, who is also in the public eye, had tested positive.

"My job made me test immediately. I had to test because it meant putting a lot of people at risk who I was working with on a new film.

"We were really lucky to get tested really quickly. I quarantined myself and have been here ever since.

Read Also: I didn't have symptoms - Idris Elba after testing positive for coronavirus

"I wasn't showing any symptoms but I am very glad I made that decision to get tested.

Idris is now self-isolating [Photo: AFP via Getty Images]

"I have been out of contact with everyone since. The early testing is the way we need to approach this.

"It's hard to say when I contracted the disease. I was exposed to it from March 4th."

The Luther actor also issued a plea to fans to keep a level head - and not circulate conspiracy theories about the virus.

"Please stop sending conspiracy theory nonsense about black people not being able to get coronavirus," he scolded, "It's dumb and very dangerous.

"Now is not the time. People need to know the facts."

Read Also: Idris Elba met with Canadian PM's wife before both tested positive

Announcing his diagnosis earlier this week, Idris revealed: "This morning I tested positive for COVID-19.

"I feel OK, I have no symptoms so far but have been isolated since I found out about my possible exposure to the virus.

"Stay home people and be pragmatic. I will keep you updated on how I'm doing. No panic."