Germany's Aston Martin driver Sebastian Vettel will retire at the end of the Formula One season, the 35-year-old four-times world champion said on Thursday.
His team had sounded confident that he would sign a new contract, but Vettel has instead decided to walk away in November. He made the announcement in Budapest ahead of this weekend's Hungarian Grand Prix.
"The decision to retire has been a difficult one for me to take, and I have spent a lot of time thinking about it," he said in a statement.
"At the end of the year I want to take some more time to reflect on what I will focus on next. It is very clear to me that, being a father, I want to spend more time with my family.”
"But today is not about saying goodbye. Rather, it is about saying thank you – to everyone – not least to the fans, without whose passionate support Formula One could not exist."
He won his four world titles in a row for Red Bull between 2010 and 2013. A subsequent big move to glamour team Ferrari did not work out at all and he has struggled to shine in a disappointing Aston Martin car over the past two seasons.
Vettel has won 53 F1 grands prix overall and was effectively the heir to Michael Schumacher as Germany's motorsport hero.
He burst onto the scene in extraordinary fashion, winning the 2008 Italian Grand Prix from nowhere for smaller team Toro Rosso.
From then on he was destined to be an F1 star but never captured the German public's imagination like Schumacher, with his dominant spell at Red Bull characterized by often boring races where he led from pole.
In latter years he has been at the forefront of F1's push to become more environmentally friendly. He has criticized the sport for its energy-sapping excesses and has also been campaigning for free speech for drivers.
At this year's Azerbaijan Grand Prix, Vettel wore a T-shirt with the words "friends" and "peace" written on in Russian, with two hands depicted shaking hands. In addition, he wore sweatbands in the blue and yellow colours of Ukraine.
Vettel had already spoken out several times against the backdrop of the Russian invasion of Ukraine.
His Aston Martin team paid tribute to his legacy.
"We made it clear to him that we wanted him to continue with us next year, but in the end he has done what he feels is right for himself and his family, and of course we respect that," team owner Lawrence Stroll said.
"He has driven some fantastic races for us, and, behind the scenes, his experience and expertise with our engineers have been extremely valuable. He is one of the all-time greats of Formula One, and it has been a privilege to have been able to work with him."
Red Bull, who won their first driver's title since Vettel's haul with current championship leader Max Verstappen last year, said in a tweet: "Thanks, Seb. Cheers for the great times and the four World Championships."
He is currently 14th in the standings, just ahead of fellow German and Michael's son Mick Schumacher, and will sign off at the season-ending Abu Dhabi Grand Prix on November 20 – his 300th F1 race.
His replacement at Aston Martin has yet to be announced.