George Russell has been confirmed as a Williams race driver for 2019 after signing a multi-year deal with the British team.
Russell is a Mercedes junior driver and currently leads the Formula 2 championship by 37 points with just two races remaining. He has tested for Mercedes and Force India over the past two years and has been in talks with Williams, which is a Mercedes engine customer, about a race seat since the summer.
On Wednesday the new multi-year deal was confirmed, which will keep him at the team until at least 2020.
"It is a huge honour to join a team of Williams' prestige and heritage," Russell said. "Formula One has been a life-long dream. From watching the races when I was a child, it feels surreal that I will now be lining up on the grid, alongside drivers whom I have admired for years.
"I would like to thank Claire [Williams, deputy team principal] and everyone at Williams for their faith in making this decision, as well as Toto [Wolff, Mercedes team boss] and the team at Mercedes for their fantastic support throughout GP3 and Formula 2.
"I am incredibly excited to start working with everyone at Grove and to take my first steps as a Formula One race driver. I cannot wait for Melbourne next year and to join Williams at the start of what we all believe will be the start of an exciting new journey."
Williams has struggled for performance over past few seasons and has dropped to new lows this year after scoring just seven points in 16 races. It looks set to finish last in this year's constructors' championship -- its worst result in its 41-year history.
Russell will be the first British driver to complete a full season with Williams since Jenson Button in 2000 and hopes to be part of the British team's turnaround.
"I am delighted to announce that George Russell will be joining Williams from the 2019 season," deputy team principal Claire Williams said. "We have always tried to promote and develop young talent at Williams, and George fits that ethos perfectly. He is already highly regarded in the paddock and a driver whose career we have been watching for a while.
"In the time we have spent with him so far, we believe that he will be a great fit for our team; his commitment, passion and dedication is exactly what we need to drive the positive momentum building at Grove as we focus on the future. We are extremely excited to welcome George and work with him moving forward."
The identity of Russell's teammate has yet to be confirmed, but current Williams driver Lance Stroll is due to leave the team at the end of the year to join Force India, which is now owned by his father Lawrence Stroll. Current Williams driver Sergey Sirotkin remains a strong candidate, as does reserve driver Robert Kubica, with both teams offering financial packages to bring to the team.
Russell joins fellow Brits Lewis Hamilton and McLaren 2019 driver Lando Norris on the grid next year.