Lance Stroll's father has confirmed growing reports that the Canadian driver will definitely be on the Formula 1 grid in 2017.

Reports have suggested that Williams are only delaying the announcement because they are waiting for Stroll to turn 18 later this month, in deference to the team's alcohol sponsor Martini.

Lance's father is Lawrence Stroll, a Canadian fashion billionaire, who is rumoured to be buying into Williams.

He told the Journal de Montreal: "Lance will be in F1 next year. You can write it in black and white."

New European F3 champion Lance is currently a Williams development driver, and taking part in a special test programme in one of the British team's 2014 cars.

It is suggested that Lance's successful campaign this year has been significantly backed by his father, with Williams even installing engineers at the Prema team.

However, Lawrence insisted that his son has also worked hard.

"You cannot know how hard he has worked since the beginning of his career," he said. "The road was long and arduous at times, but this (F3 championship) is the best reward.

"Now he reaches his ultimate goal of F1. I am convinced he will be successful."

Asked if Canadian journalists should make their travel plans for the first race in Melbourne next March, Lawrence said: "Yes, I strongly recommend it."

It is rumoured that Williams's official announcement of the Stroll deal will take place in London on November 3, but Lawrence is not confirming it.

"We are studying two [team] options," he said. "You will know everything in a few weeks."

There is plenty of scepticism about Stroll's rapid rise to F1, especially when the 2014 F3 champion, Esteban Ocon, had to spend a year in GP3 before making the jump.

Yet Ocon said: "If I had been as fortunate, I would have done the same thing.

"The transition from F3 to F1 is possible, as demonstrated by other drivers. He clearly deserves his place in F1."

The 2016 season continues on Sunday with the United States Grand Prix.