"It remains to be seen what will be the performance of the car and his own performance," Alonso said. "But if he's at 100 percent he'll be amazing to watch." It completes a remarkable comeback for Kubica, rated as one of the quickest in F1 before a gruesome rally accident in 2011 left him needing seven hours of surgery on a partially severed right hand.

"Being back on the F1 grid next season will be one of the greatest achievements of my life," Kubica said. "I cannot wait to get back racing." Kubica impressed in testing for Williams last year and was a reserve and development driver this year. One of the main questions regarding his return was whether Kubica's fragile right arm could handle the strain of a heavy car.

Those questions were answered when he successfully completed a rigorous rehabilitation program.

"I would like to thank everyone who has helped me during what was a difficult period of my life over these last few years," Kubica said. "It has been a challenging journey to make it back to the Formula One grid, but what seemed almost impossible is now possible."

Kubica earned 12 podium finishes in F1 from 2006-10 — claiming his first pole position and victory in 2008 — and was considered among the series' brightest talents.

Kubica won the Canadian GP driving for BMW Sauber after placing second at the Monaco GP. Those performances moved him reportedly close to joining Ferrari and a better title shot.

Now he's just happy to be back racing in F1.

Associated Press