Robert Kubica looks certain to secure the second race seat at Williams for 2019.
At an event in northern Poland, the British team's reserve driver declared: "I have made my decision."
Pole Kubica, who has not raced in F1 since almost severing his forearm in a 2011 rally crash, was reportedly tossing up between the Williams race seat and a Ferrari test role.
He is believed to have put together enough funds to secure the Williams seat, including millions from Polish oil company PKN Orlen.
Sport.pl quotes Kubica as saying: "Will I be in Williams next year? I hope.
"There are only two teams that officially have places next year, and I will definitely not go to Toro Rosso."
However, 33-year-old Kubica suggests it has not been a simple period of negotiations.
"The period is very tense with many things happening," he said. "It is not like me or other people are having fun and do not want to announce what is decided.
"Everyone has to make their decisions. I openly said that I was approaching my decisions with a deadline, and I have already taken it.
"I will not say it so as not to create strange consequences, but I think that now we should find out very quickly what happens next with me.
"As of today, not everything depends on me, but I can also say that not everything depends on Williams," Kubica added.
It could be that Williams is waiting for Force India to announce that Lance Stroll is heading to the Silverstone based team for 2019.
