Former world champion Mika Hakkinen has admitted that switching teams within Formula 1 is an easy and unemotional task for most drivers.
"Lewis has been with McLaren for so many years and I think, for him, it was time to change," Hakkinen told BBC Radio Five Live. "It's just a job to be honest.
"There are no emotional feelings about it, you are there to win, you are racing with the team and you do your maximum for the team. Lewis has now moved to Mercedes and that is going to be interesting because his teammate Nico Rosberg is also a very quick driver."
The new F1 campaign gets underway in Australia next month.