Maximilian Reinelt, an Olympic gold medallist rower from Germany
who was a long-time member of the country's successful men's eights crew, has died aged 30.
Police in the Swiss canton (state) of Graubuenden said Reinelt collapsed while cross-country skiing in St. Moritz over the weekend.
The cause of death was not announced.
Reinelt won Olympic gold at the 2012 London Games and silver four years later in Rio de Janeiro.
The German rowing federation said Reinelt ended his competitive career after the 2016 Olympics to complete his medical studies, and was soon to work as a team doctor with a German under-23 squad.
Reinelt also won two world championship gold medals and multiple European titles.
A statement released by Team Germany read: 'He was first and foremost a friend, someone we could rely on not just in training and competition, but throughout our lives.
'At the moment we find it incredibly difficult to find the appropriate words to honour Maximilian's life, for he can no longer be part of our community exceeds our imagination.
'Our thoughts and sympathy are with his fiancee, his parents and siblings.'
Siegfried Kaidel, chairman of the German Rowing Federation, said: 'His surprise death which came far too early makes me indefinitely sad.
'Everyone who knew him was captivated by his friendly nature. He will be missed.'
Reinelt, who hailed from Ulm in southern Germany, first started competing for his country as a junior in 2006.
When the German eight took gold at the 2012 Olympic in London it was the first time they had won the event since 1988.
That success came hot off the heels of German wins at the 2010 and 2011 World Championships, while they demonstrated their prowess with four consecutive European Championship wins between 2013 and 2016.
Following silver at the 2016 Olympics in Brazil, Reinelt retired to concentrate on studying medicine in Bochum and had just been appointed doctor for the German under-23 rowing squad.
He had been scheduled to attend their rowing camp in Mequinenza, Spain this week.