Idris Elba was pictured with Justin Trudeau's wife Sophie less than two weeks before they both tested positive for coronavirus.
The Luther star and Hollywood actor revealed yesterday that he had tested positive for COVID-19 and had gone into immediate self-isolation.
Idris, 47, had no symptoms but got tested after coming into contact with someone who had tested positive.
It's not known who that other person is.
But it's since been revealed that Idris had met with the Canadian Prime Minister's wife, Sophie Grégoire Trudeau, less than two weeks before they both tested positive.
They both attended the We Day UK charity event at the SSE Arena in Wembley and posed for photographs with attendees and other celebrities, including Lewis Hamilton.
Idris was at the event to talk about social issues with 12,000 schoolchildren and teachers.
Sophie has been working alongside the charity.
Sharing a picture from the event at the time, she wrote on Instagram: "My heart is full after spending time working with my own family and the WE family. Our message in London: Show yourself love and offer that same love to the world."
Sophie announced last week that she had tested positive for the virus and had gone into self-quarantine.
Idris has said he is "feeling OK" after contracting coronavirus but is worried about it because he suffers from asthma.
In a live broadcast on social media, the actor said: "I have asthma, so I sort of fit into the high category of most at risk.
"I have a respiratory issue and I have had asthma all my life.
"Catching corona was definitely not on my bucket list at all but even my asthma is OK."
He added: "Of course I'm worried. I'm worried about having the virus, I'm worried about having asthma and how that could make things really complicated for me really quickly."
He said he was inspired to share information about what having the virus is like by fellow actor Tom Hanks, who has also tested positive for COVID-19.