London: Lewis Hamilton said he was determined to leave Mercedes on a high this season before fulfilling a childhood dream by racing for Ferrari in 2025.
Britain's seven-times Formula One world champion stunned the sport when his move on a multi-year deal was announced on Thursday.
Hamilton, 39, said in a post on Instagram on Saturday that the decision felt right and reminded him of his move to Mercedes from McLaren at the end of 2012.
"I feel incredibly fortunate, after achieving things with Mercedes that I could only have dreamed of as a kid, that I now have the chance to fulfil another childhood dream. Driving in Ferrari red," he wrote.
"Mercedes has been a huge part of my life since I was 13 years old, so this decision has been the hardest I've ever had to make," he added.
Hamilton said the time was right to take on a new challenge.
"I still remember the feeling of taking a leap of faith into the unknown when I first joined Mercedes in 2013," he recalled.
"I know some people didn't understand it at the time but I was right to make the move then and it's the feeling I have again now. I'm excited to see what I can bring to this new opportunity and what we can do together."
Ferrari have not won a drivers' title since 2007, the year Hamilton made a stunning debut with McLaren and missed becoming champion by a single point.
He won his first title with McLaren in 2008 and the rest with Mercedes.
The Briton is now the sport's most successful driver of all time with a record 103 wins, although his last victory was in December 2021.
Hamilton said that right now he was not thinking of 2025.
"My focus is on the upcoming season and getting back out on track with Mercedes," he said. "I am more driven than ever, I am fitter and more focussed than ever and I want to help Mercedes win once again.
"I am 100% committed to the job I need to do and determined to end my partnership with the team on a high."
The record 24-race season starts in Bahrain on March 2.