Mercedes reserve driver George Russell has joined Williams for the 2019 season after signing a multi-year deal.
The 20-year-old, who has driven in practice sessions for Force India and also carried out testing work for Mercedes, will line up on the grid for his Formula One debut at the Australian Grand Prix in March next year.
Russell leads the Formula 2 title race by 37 points with only one round of the season remaining and is the reigning GP3 champion.
The Brit, who joined the Mercedes junior programme at the start of last year, will fill one seat for Williams, who are yet to confirm the identity of Russell's team-mate.
"It is a huge honour to join a team of Williams' prestige and heritage. Formula One has been a life-long dream." said Russell.
"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."
Deputy team principal Claire Williams revealed Russell has been on Williams' radar for a while.
"I am delighted to announce that George Russell will be joining Williams from the 2019 season. We have always tried to promote and develop young talent at Williams, and George fits that ethos perfectly." she said.
"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."
Sergey Sirotkin and Lance Stroll are Williams' current drivers, though the latter is expected to join Racing Point Force India after his father, Lawrence, led a buy-out of the team.
|Valverde not expecting Messi magical recovery|
|Wozniacki calms fears over knee injury|
|Maybe it´s my interviews - Klopp on Liverpool´s room for improvement|
|Language no barrier to Dortmund dangermen Reus and Alcacer|
|EPCR confirms no replay of Bath-Toulouse Champions Cup fixture|
|F1 Raceweek: Five the magic number as Hamilton eyes Mexico repeat|
|RFU to introduce in-season breaks for players|
|Nainggolan misses Barcelona trip|
|Wozniacki battles through knee complaint to down Kvitova|
|Alcacer: Two seasons at Barcelona not lost|
|Henderson, Keita to miss Liverpool´s Red Star clash|
|Khabib holds talks over Mayweather Moscow fight|
|Wolf in for Titz as Hamburg try to stop slump|
|Davies released from Wales squad as Evans comes in|
|Mbappe on track to match Messi and Ronaldo, says Giuly|
|Coleman, Kipchoge and Lyles among IAAF Male World Athlete of the Year shortlist|
|Serena Williams will win slams again sooner or later, says Seles|
|You always want the best – Ter Stegen open to Neymar return|
|Xavi: My teams will never use Mourinho´s style|
|I knew what I got myself into - LeBron appreciates Lakers are a work in progress|
|Mourinho: Ronaldo loves United but he will want to score|
|Cooper completes Rebels move and takes parting shot at Reds coach Thorn|
|Bellerin amazed by ´born champion´ Ozil|
|Penguins, kangaroos and ´Stone Cold´ Steve Austin: Halloween comes early for Trail Blazers|
|Ronaldo gunning for United, Aguero targets double record - Champions League in Opta numbers|
|Ill Vardy couldn´t stomach penalty decision – Puel|
|LeBron´s Lakers lose again, Magic stun Celtics|
|Bartomeu: No Barca return for Neymar, Valverde contracted until 2020|
|Simmons and ´stimulating´ 76ers in NBA Finals mix, says Longley|
|Falcons heap further misery on Giants|
|Vidic hails Ronaldo as ultimate professional ahead of Old Trafford return|
|Warriors´ Cousins nearing NBA return|
|Pogba can´t do the basics – Souness criticises Man United star|
|Messi absence big blow for Barca as Icardi talks up Inter|
|´You can´t cry, that´s true´ – Ronaldo responds to Isco|
|Bartomeu: Barca still competitive without Messi|
|Bills RB McCoy remains in concussion protocol|
|Raiders place Marshawn Lynch on IR|
|Emery calm over title talk after another Arsenal win|
|Green: Warriors have to clean up defensively|
|Mariners say Bolt talks ongoing amid reports contract offer was rejected|
|Proud captain Ozil revels in Arsenal´s ´sexy football´|
|Puel angry over Holding handball|
|Cilic breezes through in Basel, Anderson fights back|
|Ingram: Four-game ban better than we expected|
|Raiders send Cooper to Cowboys for first-round pick|
|Arsenal 3 Leicester City 1: Outstanding Ozil inspires comeback win|
|World Series 2018: Three reasons why the Dodgers will win|
|Yarmolenko out for six months after Achilles surgery|
|World Series 2018: Three reasons why the Red Sox will win|
|Ozil eclipses Klinsmann to become Premier League´s most prolific German|
|Allegri expecting Old Trafford battle against Mourinho´s United|
|Bertens feared she did not belong in Kerber clash|
|Returning Ronaldo expecting ´tough´ game against Manchester United|
|Cristiano Ronaldo confident of clearing his name amid rape allegation|
|Osaka looking to learn from losing start in Singapore|
|Kovac expects tough test against AEK Athens|
|Whyte gives Chisora deadline over rematch|
|Spartak Moscow sack Massimo Carrera|
|Atletico Madrid confirm fresh injury issue for Gimenez|
|Dolberg extends Ajax contract after Real Madrid links|
|Ronaldo an example for Lukaku to follow|
|Bertens battles back to blast past Kerber|
|Ramos apologises for training ground fracas|
|Raikkonen should take heed of Alonso misfortune as F1 career winds down|
|Guardiola wants Manchester City fans to push team to Champions League glory|
|Isco not interested in departed Ronaldo - he didn´t want to be here|
|World Series 2018: Three storylines to watch in Red Sox-Dodgers|
|Neymar focus bad for football - PSG´s Maxwell|
|Marco Ianni charged by FA over Jose Mourinho touchline row|