McLaren racing director Eric Boullier has confirmed Jenson Button will be the team's official test and reserve driver for the 2017 F1 world championship.

The 2009 F1 world champion is set for a one-year sabbatical from the sport with Stoffel Vandoorne stepping up to a race seat alongside team-mate Fernando Alonso this season.

Button was not present at the McLaren MCL32 F1 launch which fuelled speculation the British driver would take less of a hands-on role in 2017 after his being relieved to leave the sport at last year's season finale in Abu Dhabi.

Boullier was quizzed on the issue at the McLaren team launch, after the Woking-based team announced Lando Norris had joined the team's junior programme, with the team boss stating Button's role hadn't changed since its initial announcement last September.

"The official reserve driver is Jenson Button, there are no changes," Boullier said. "He will be doing some simulator work for us and coming to some of the races and a lot of events because he is a McLaren ambassador."

Button posted his support of McLaren's team launch on Twitter and is currently out in the USA.

Super cool launch footage, go get it boys! https://t.co/THBw8APd7G-- Jenson Button (@JensonButton) February 24, 2017

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