Nico Rosberg shocked the Formula 1 world when he retired as word champion in 2016, and now he has lifted the lid on his decision - and how Toto Wolff took it.
Lewis Hamilton was already a three-time world champion - the previous two seasons with Mercedes - when his team-mate swept to the title in 2016, five points clear of the Englishman.
The German had emerged as a superstar in his own right, but almost immediately after taking the top prize, he announced his retirement, and he hasn't been behind the wheel of an F1 car since.
While Hamilton went on to win a further four world titles with Mercedes, Rosberg has since become a successful eco-entrepreneur - something he is passionate about but doesn't necessarily give him the same buzz.
"It was the perfect exit," Rosberg said. "My dream was to win the championship, once, and that was more than I thought I'd be able to do anyways. So I got the championship. I decided, I felt that it was a great opportunity to move on at the highest point.
"To be at the pinnacle of a sport is so huge and after that it's like everything else, forever, will be less intense than that," he said.
"We were actually sitting together on a flight, even having dinner in the flight together, but I was scared that I would burst out in tears if I mentioned this now so I decided 'I'm going to chicken out!' - so I just called him right when we left the plane!