Robert Kubica has joined Alfa Romeo as their 2020 reserve driver, the role the Pole carried out 14 years ago when he made his Formula One debut with the Swiss-based team then known as BMW Sauber.
The deal -- announced on Wednesday -- also sees Polish oil company PKN ORLEN, who backed the 35-year-old's comeback last season at former champions Williams, become a co-title sponsor of the team in a multi-year partnership.
Kubica's big break came in 2006 when he became Poland's first F1 racer, replacing Canada's 1997 world champion Jacques Villeneuve at BMW Sauber and going on to win with them at the 2008 Canadian Grand Prix.
The Pole, who suffered a near-fatal rally accident in 2011 that partially severed his right arm, scored Williams' only point last year in a remarkable personal comeback clouded by the team's inability to provide a competitive car.
He announced in September that he was leaving and has since been replaced by Canadian Nicholas Latifi, the team's 2019 reserve.
"I'm starting a new chapter in my career by joining Alfa Romeo Racing ORLEN," Kubica said in a statement. "This is a team that has a special place in my heart and it'll be nice to see the familiar faces I still remember from Hinwil [in Switzerland].
"Time and circumstances are obviously different, but I am convinced that I will find the same determination and hunger to succeed."
Kubica had also been linked to the Haas and Racing Point teams, who had considered him for a role as a tester and simulator driver.
Ferrari-powered Alfa Romeo's race drivers this year are Finland's 2007 world champion Kimi Raikkonen and Italian Antonio Giovinazzi, an unchanged lineup from 2019.
Kubica, who before his accident raced for Renault and was close to becoming a Ferrari driver, was welcomed back to the Hinwil factory by team principal Frederic Vasseur.
"He is a driver that needs no introduction: one of the most brilliant in his generation and one who displayed the true meaning of human determination in his fight to return to racing after his rallying accident," Vasseur said.
"His feedback will be invaluable as we continue to push our team towards the front of the grid."
Alfa Romeo finished last season in eighth place with 57 points.
The team said PKN ORLEN branding will feature on the C39 car and all "trackside assets".