Robert Kubica has admitted that he came tantalisingly close to pulling off a fairytale return to Formula 1 for 2018.

Instead, Williams opted for the well-sponsored Russian Sergey Sirotkin, although Pole Kubica said that his comeback dream is still alive thanks to the reserve and Friday practice role.

"For me this is already a return to formula one," he told Polish sports daily Przeglad Sportowy.

"It's like a second beginning, because I'm back in the same role in which I found myself before my debut in 2006."

The 33-year-old said that he will attend almost all of the 21 grands prix this year, but admitted that walking into the paddock will actually be bittersweet.

"I thought about it and to be honest I do not think it will be a nice moment," Kubica said when asked about the forthcoming Australian Grand Prix.

"Being there to see other drivers race will not be nice, but it is also worth trying to come back.

"It will also not be the typical third driver role where you come to the race and do little else. For me the most important is the possibility of driving the current car.

"If I did not have that, I would not have taken this job because it wouldn't have made sense. Only by driving can I have the chance to take the last, most difficult step."

Asked how different he is now compared to the driver he was prior to his serious arm injury in 2011, Kubica answered: "I'm further away now than I was a few months ago!

"But I think the next seven, eight, nine months can bring me closer again. I don't really know how close it was, but it doesn't matter.

"As a rule, I have the habit of believing in things only when they happen. But at one point I was almost convinced that I would be racing in Australia."

The new season gets underway in a little over a month.