Daniel Ricciardo has paid tribute to Robert Kubica for returning to Formula 1 eight years after suffering life-changing injuries in a rally crash.
Kubica, who will drive for Williams this season, has only partial movement in his right arm after it was partially severed in the accident in 2011.
Renault driver Ricciardo said: "I don't think we all know the extent of what he has been through to get back here.
"It is a testament to his character but it's awesome to see him back."
The Pole, now 34, was one of the leading drivers in F1 when he had the accident in which he also suffered several other major injuries.
He has been through extensive recovery and rehabilitation in the intervening period, including competing in the world rally championship for a couple of years.
Kubica, who won the 2008 Canadian Grand Prix for BMW Sauber, almost won a Williams drive in 2018 but was passed over in favour of Russian Sergey Sirotkin.
But Williams dropped Sirotkin at the end of last season after being convinced Kubica was up to the task of returning.
Kubica's injuries mean he cannot grip a steering wheel in the conventional way with his right hand, on which his fingers do not fully close, and certain controls for the car have had to be re-sited as a result.
But he insists that he is able to drive competitively despite what he refers to as his "limitations", although he has said he cannot yet say whether he is able to reach the high levels he attained in his first career.
Asked how he felt about finally being able to make a return, Kubica said: "It has been a long time away from the sport. Not really a lot of time to think about the emotions. You are focused on the job and learn as much as you can about the new F1 and trying to be ready."
Williams, whose car was two and a half days late for the start of pre-season testing, are expecting to start the new season in Australia this weekend in last place but hope to improve as the season goes on.
"We didn't have a perfect start to winter testing," Kubica said. "Let's see. We just have to maximise what we have."