CONFIRMED: Bottas joins Mercedes.

Lewis Hamilton's team-mate revealed

CONFIRMED: Bottas joins Mercedes.

Formula One's worst kept secret is out.

Finland's Valtteri Bottas has been confirmed as Nico Rosberg's replacement at Mercedes.

The Williams driver was the hot favourite for the drive after he was spotted at the team's factory before Christmas.

His manager Toto Wolff also runs his new team.

Rosberg vacated one of the hottest seats in F1 after winning the world championship.

But his relationship with team-mate Lewis Hamilton soured when the pair clashed a number of times on track in 2016.

For his part, Valtteri says he's got no issues with the Brit.

Williams haven't mucked around in finding a replacement for their star driver, convincing Felipe Massa to come out of retirement.

In other Formula One movement, Mercedes test driver Pascal Wehrlein will drive for Sauber this season.

The 2017 season roars to life in Melbourne for the Australian Grand Prix from March 24-26.