Sam Michael will join McLaren for the final two races of the season after he was given permission to start work for the Woking-based outfit by former employers Williams, AUTOSPORT can reveal.
The Australian left Williams at the end of September after a lengthy spell as its technical director, having agreed a deal to join McLaren as its sporting director.
At the time it was unclear how long Michael would have to spend on 'gardening leave', while he served out the terms of his old contract.
His original deal meant he could have been forced to sit out until March next year, which would have left him with very little preparation time ahead of the 2012 season.
However, following discussions between Williams and McLaren, sources have confirmed that Michael was allowed to begin work officially at his new team from November 1, having been out of action for just one month.
He began duties at the factory on Tuesday and will now travel to the Abu Dhabi and Brazilian Grands Prix with the Woking-based outfit.
Speaking in September, Michael said that the chance to see McLaren in action at the track before the end of this season would be a great boost.
"If I can get to a race this year with McLaren, it lets me observe what they are up to," he told AUTOSPORT. "It's much better to do that and have the winter to think about things rather than going straight in at Melbourne and reacting to what I see."