Sebastian Vettel has played down reports that he might try to launch a return to the Formula 1 grid.

The quadruple world champion called it a day at the end of last year, but Red Bull's Dr Helmut Marko this week said of the 36-year-old: "I'm not sure he knows exactly what he wants.

"However, I do not believe that the driving chapter is completely closed for him."

Vettel then admitted he is still "in contact" with the team at which he achieved his monumental success in F1 - amid reports he will attend the Japanese GP at Suzuka next weekend.

However, he said it's for an undisclosed "project" - almost certainly on the environmental front - rather than talks with F1 teams about a potential return.

"I can't make any announcements at the moment, but I'm also very excited about it," Vettel said of his impending trip to Japan. "I am very happy to be visiting Japan again."

When asked if he has ever thought about returning to the grid, he laughed: "There's plenty of time to think every day.

"No one knows for sure, but I can tell you right now - there will be no return to F1."

Vettel insists he is not "jealous" of the dominance Max Verstappen is currently enjoying at Red Bull.

"He is working really hard and I think he will win even more. But I'm not jealous. I am happy to see his success.

"My F1 career is over. What that means is that I can now enjoy watching my former rivals perform from a distance."

Vettel also played down the likelihood of a return to F1 in a non-drivin role.

"If I go to Zandvoort," he laughed again, "I'd rather relax on the beach." body check tags ::