Fernando Alonso is to leave Formula One at the end of the season, McLaren have confirmed.
The 37-year-old has had a glittering career in F1, winning back-to-back titles in 2005 and 2006 with Renault, the first of which made him the then youngest ever champion.
Alonso, who is in his 17th season in the sport, has won 32 races, amassed 22 pole positions and reached the podium on 97 occasions.
"After 17 wonderful years in this amazing sport, it's time for me to make a change and move on. I have enjoyed every single minute of those incredible seasons and I cannot thank enough the people who have contributed to make them all so special," he said via a McLaren statement.
"There are still several grands prix to go this season, and I will take part in them with more commitment and passion than ever.
"Let's see what the future brings; new exciting challenges are around the corner. I'm having one of the happiest times ever in my life but I need to go on exploring new adventures."
McLaren Racing today confirms that double F1 World Champion Fernando Alonso will not race in Formula 1 in 2019. https://t.co/hbOCGZP3E2
— McLaren (@McLarenF1) August 14, 2018
Alonso, whose McLaren contract runs out at the end of this season, has cut a frustrated figure in recent years with the team unable to provide the talented Spaniard with a car capable of competing at the top end of the grid.
Before Tuesday's announcement, Alonso had been linked with Red Bull or a return to Ferrari, but he has also been heavily tipped to race in IndyCar having previously appeared in the series.
While confirming that he will not race in F1 next season, Alonso seemingly did not fully close the door on a future return.
He added: "I want to thank everyone at McLaren. My heart is with the team forever.
"I know they will come back stronger and better in the future and it could be the right moment for me to be back in the series; that would make me really happy.
"I have built so many great relationships with many fantastic people at McLaren, and they have given me the opportunity to broaden my horizons and race in other categories.
"I feel I am a more complete driver now than ever."
A move to IndyCar would make the most sense in terms of Alonso's ambitions to complete motorsport's triple crown.
Victories at the Monaco Grand Prix and Le Mans 24 Hours means he has two of those three legs, leaving just the Indianapolis 500 – which he raced in 2017 - to check off the list.
Alonso's first drive in F1 came with Minardi, before he was later promoted to a race seat at Renault after impressing as a test driver.
After winning his two world titles with the team, Alonso joined McLaren in 2007 but a difficult working relationship with Lewis Hamilton led to a return to Renault just a year later.
Ferrari came calling in 2010 but he failed to win a another world title, finishing runner-up on three occasions before starting his second stint with McLaren in 2015, only for problems with their Honda engine partnership to end any hopes of him being competitive.