Felipe Massa is to part company with Williams F1 at the end of the current season. The team made the announcement in a press release on Saturday.
Massa originally retired from Formula 1 at the end of last year. He was coaxed back when Valtteri Bottas was signed up by Mercedes over the winter, leaving Williams short-handed for 2017.
Massa had signalled that he was in no mood to retire again anytime soon. However today's announcement means the end of a long Grand Prix career for the 36-year-old comprising 267 starts, 16 poles and 11 victories.
“As everyone knows, after announcing my retirement from Formula 1 last year, I agreed to return this season to help Williams when the call came," said Massa.
"I have now enjoyed four great years with the team, but my career in Formula 1 will finally come to an end this season.
"Once more, I would like to say a big thank you to everyone who has supported me throughout this time: my wife and my father, my whole family, my manager Nicolas and all my friends, colleagues and sponsors.
"I would also like to add a huge thank you to all of the fans who have been incredibly supportive and passionate over the years."
The timing of the announcement means that Massa can now head to his home Grand Prix next week knowing his future. It means that he will be able to share the moment with his legion of fans.
"I take so many great memories with me as I prepare for my final two races in Brazil and Abu Dhabi," he said. "Although they will be emotional, I am looking forward to ending on a high note and preparing for a new chapter in my career.”
Williams deputy team principal Claire Williams thanked Massa for his contribution to the team over the years.
“I would like to thank Felipe for all he has done for the team," she said. "It has been an absolute pleasure to work with him.
"We are especially grateful that he agreed to postpone his retirement from Formula 1 for a year, after Valtteri joined Mercedes, which demonstrated the depth of the relationship we built during our time together.
"We appreciate that it wasn’t an easy decision for him to return, after having such an emotional send-off at the end of last year.
"On behalf of Sir Frank, and all the team, we give our very best wishes to Felipe for the future."
The team added that it would make a decision on its driver line-up for 2018 in due course. Lance Stroll will stay with Williams for a second year, but it's not yet known who will take Massa's place as his team mate.
Robert Kubica and Paul di Resta have both had recent tests with Williams with a view to signing them. Daniil Kvyat's name has also been added to the list since his exit from Toro Rosso was confirmed.