Three French sports personalities are among 10 people killed in a helicopter crash in Argentina, the French presidential office confirms.
They were taking part in filming for a reality television programme about survival.
Those killed include Camille Muffat, a swimmer who won a gold medal in London in 2012, Alexis Vastine, an Olympic boxer, and Florence Arthaud, a sailor.
The two helicopter pilots also died in the crash.
"The sudden death of our fellow French nationals is a cause of immense sadness," said a statement from French President Francois Hollande.
The helicopters collided during filming near Villa Castelli, about 1,170km from Buenos Aires, according to local officials.
The sport stars had been taking part in Dropped, a popular celebrity show on the channel TF1.
The show flies celebrities into rough terrain by helicopter and films their attempts to find food and shelter.
France in mourning
France is waking up to the shock of its loss, with the death of the three sports stars and five other French nationals splashed across every paper.
Prime Minister Manuel Valls tweeted his "immense sadness" saying "all France is grieving this morning".
Meanwhile Culture Minister Fleur Pellerin told the BFM-TV news channel that the three athletes were "among the most outstanding ambassadors for our country".
Former Arsenal and France striker Sylvain Wiltord, who was taking part in the current series, said via social media, "I'm trembling, I can't talk. I'm horrified." And a former team-mate of Camille Muffat, Yannick Agnel said simply: "not her… Let us be strong."
But amid the horror there are also the first signs of anger. Well-known musician Benjamin Bioley has criticised what he called a "horrible TV reality show that serves up cardboard stars and then steals three wonderful athletes".
As the country begins to absorb the news, the questions over this incident and the circumstances that led to it will only grow.