Hamilton insists Mercedes story can end on a high
The 39-year-old Briton has been with Mercedes since 2013, but recently activated a break clause to seal a move to the Italian team in 2025.
"An opportunity came up in the New Year and I decided to take it," Hamilton said, describing the decision as the hardest he'd ever faced.
"We have had an incredible journey together, created history within the sport and it is something I take a lot of pride in," he said.
Hamilton -- without a win in two years -- won six of his record-equalling seven world championships with the Silver Arrows.
"This chapter is still not finished and I am still 100 percent focused on delivering for this team," he insisted Friday.
Mercedes have struggled to match their rival Max Verstappen of Red Bull since Hamilton missed out on what would have been a record eighth world championship in 2021 in controversial fashion.
Current Formula One world champion Verstappen won 19 out of last season's 22 races as he surged towards a third consecutive Drivers' Championship.
The opening Grand Prix of the F1 season is set for Bahrain on March 2.