Hamilton’s contract with the team where he has raced since 2013 was set to run out at the end of this year, but he has long been expected to complete an extension.
Russell is understood to have already been contracted to race with Mercedes until the end of the 2024 campaign as part of the long-term deal he signed to join the team back in 2021, but the announcement made on Thursday at the 2023 Italian Grand Prix extends that deal for an additional season.
F1 driver contracts: How long are all the drivers' contracts?
“We dream every day of being the best and we have dedicated the past decade together to achieving that goal,” said Hamilton.
“Being at the top does not happen overnight or over a short period of time, it takes commitment, hard work and dedication and it's been an honour to earn our way into the history books with this incredible team.
"We have never been hungrier to win. We have learnt from every success but also every setback.
"We continue to chase our dreams, we continue to fight no matter the challenge and we will win again. I'm grateful to the team who have supported me both on and off the track.
"Our story isn't finished, we are determined to achieve more together and we won't stop until we do."
Russell said: "I have grown up with this team ever since joining as part of the junior programme back in 2017.
“It's my home and it feels fantastic to extend our special relationship through 2025.
"After stepping up to the Mercedes race seat last year, I wanted to reward the trust and belief that Toto [Wolff, team principal] and the rest of the team placed in me.”
Hamilton’s contract extension had been in the work for a long time in 2023, but speculation about when it would finally be announced or if a shock switch to another squad – such as the rumours that Ferrari was considering making him an offer ahead of this year’s Monaco GP – could be in the works had started to build.
This had increased after Wolff’s assertation at a conference in New York ahead of the Canadian GP that Hamilton’s new deal would be announced in “days” failed to come to fruition, but team insiders always maintained the delay was purely due to typical contract legal wrangling.
"Continuing with our current driver line-up was a straightforward decision,” said Wolff.
“We have the strongest pairing on the grid and both drivers are playing a crucial role in the team to move us forward.
“The strength and stability they provide will be key building blocks for our future success.
"Our partnership with Lewis is one of the most successful in the sport's history.
“It was always a formality that we would continue together - and it's energising for us all to be confirming that publicly.
“His qualities as a pure racing driver are illustrated by his remarkable track record; but over our years together, he has grown to become a pillar and leader of our team.
“Those leadership qualities are crucial as we focus on fighting for world championships again.
“As F1's biggest global star, he has also played a key role in shaping our commitments to diversity, inclusion and sustainability, that will be foundations for our success in the years ahead.
"George is a leading light of his generation. He has repaid the faith we showed in him when promoting him to a race seat in 2022.
“His maiden pole position in Hungary and first Grand Prix victory in Sao Paulo were standout moments last season.
“As a driver, he combines razor-sharp speed with the tenacity of a true fighter. But he brings, too, an intelligence and attention to detail that will help him to continue to grow, develop and improve further.
“He is a natural fit to the team and we are delighted to have extended the relationship for the coming years."
This announcement means Hamilton and Russell will be paired as Mercedes team-mates for at least four seasons after the latter replaced Valtteri Bottas ahead of the 2022 campaign.
It also ends any formal hope of Ferrari’s Charles Leclerc joining Mercedes when his current deal with the Scuderia expires at the end of 2024.
