World champion Lewis Hamilton has led the tributes to Formula One race director Charlie Whiting following his death at the age of 66.
Just days before the start of the 2019 F1 season, Whiting's death was confirmed on Thursday after suffering a pulmonary embolism in Melbourne.
In a statement, FIA president Jean Todt described Whiting as "a central and inimitable figure in Formula One" and added that the sport had "lost a faithful friend and a charismatic ambassador".
The news broke ahead of the first drivers' media conference of the year, and those in attendance added their tributes to the former F1 mechanic – Whiting having worked for Nelson Piquet in his title seasons in 1981 and 1983.
"I've known Charlie since I started in 2007," said Hamilton. "Obviously incredibly shocked this morning to hear the sad news. My thoughts and prayers are with his family.
"What he did for the sport, his commitment, he really was a pillar, such an iconic figure within the sporting world, and he contributed so much to us. May he rest in peace."
Vettel revealed he had spent some time with Whiting on Wednesday walking the Albert Park track, and his death had come as a complete shock to the German.
The four-time champion said: "I was as shocked as we all are, still now, when I heard the news this morning, especially because I spoke to him yesterday and walked the track for the first couple of corners together with him.
"It's difficult to grasp when somebody's just not there anymore.
"I've known him for a long time and he was sort of our man, our drivers' man. Obviously there's regulations and all that and then there's us and he was the middle man. He was someone you could ask anything, at any time. He was open to everyone, any time his door was always open.
"He was a racer, he was just a very nice guy. The whole paddock, the whole circus, the whole family of Formula 1, all our thoughts are with him and especially his family in these difficult circumstances."
Robert Kubica – who has returned to F1 after nine years away – added: "It's a hard moment. I saw Sebastian walking with Charlie yesterday and I thought I would not interrupt them because I was going to see him on Friday in the drivers' briefing. Unfortunately that will not be the case.
"It's very sad. He was a kind of icon of Formula One but not only Formula One. He was really the kind of person you could always trust and commit, so it's a very sad moment. My thoughts are with his family."