France scrum-half Antoine Dupont has tested positive for coronavirus.
He becomes the fourth member of the French camp to contract the virus. Earlier this week head coach Fabien Galthie and his assistant William Servat both confirmed they'd also tested positive.
The France squad were subject to a fresh battery of tests on Friday.
Dupont is said to be asymptomatic, and is the only one of the 31-man squad to show a positive result. The 24-year old will enter a period of isolation and is set to miss next week's Six Nations clash with Scotland in Paris.
It's believed Dupont was seen not wearing a mask next to Galthie following the French squad's return from Dublin on Monday.
The IRFU said earlier this week that the PCR testing conducting on the Ireland panel returned entirely negative results.
Further testing took place on Wednesday, with no positives. Another round of tests was due to take place on Friday.
Of the 31 players tested on Friday, Charles Ollivon, Julien Marchand, Paul Willemse, Arthur Vincent, Cyril Baille, Dylan Cretin, Romain Taofifenua, Anthony Bouthier, Louis Carbonel, Dorian Aldegheri and Peato Mauvaka have all returned negative results.
The absence of Dupont would be a massive blow to French hopes against the Scots.
La Rochelle head coach Ronan O'Gara told OTB Sports last week that the Toulouse no.9 is currently the best player in the world.
Dupont is right up there already, he’s the best player in the world for me. He’s a serious, serious player," the former Ireland out-half said.
"When we talk about Messi and about Ronaldo, I think in five years time we’ll be talking about Dupont in the same glorified way."
O'Gara added, "What Dupont does better than anyone else is that he gets on the ball in chaos or in unstructured play and he has a go.
"It can look like there’s absolutely no gaps, no threat and then bang he goes off his left foot, he goes off his right foot and all of a sudden he’s 20 metres up the pitch.
"He’s also incredibly strong, he’s a little pocket rocket."