Williams have announced that Toto Wolff has left the team with "immediate effect" to take up a role with Mercedes-Benz.
Wolff's involvement with Williams began in 2009 when he bought shares in the Formula One team and also joined the board of directors.
Three years later the Austrian, who many believed was being groomed to take over from Sir Frank Williams who the co-founder retires, was named as the Executive Director of WilliamsF1.
Wolff, though, has now stepped down from that role with Williams announcing that the 41-year-old will leaving the company with immediate effect to take up a new role with Mercedes-Benz Grand Prix Ltd.
The team's statement added that while Wolff will be relinquishing his seat on the company's Board of Directors he will retain his shareholding.
"Toto will be relinquishing his seat on the Company's Board of Directors but will retain his shareholding.
"I would like to thank Toto for his hard work, dedication and commitment to the team during his time as a Director of the Company," said Sir Frank.
"He was a key support to me as Executive Director last season, deputising at a number of races when I was unable to attend. However, positions such as the one offered to him by Mercedes do not come around often.
"Toto has a long history with them and I certainly was not going to stand in the way of him accepting this once in a lifetime opportunity.
"Toto will retain his shareholding in Williams and will always have a place at Grove but make no mistake; we will fight him hard on the racetrack!
"I am sure he will be a strong asset for Mercedes and on behalf of the whole team I would like to wish him the best of luck in his new role.
"I'm lucky to have a very professional group of people around me and the Company's Executive Committee will continue the work they have been doing to ensure a successful future for the business."
Any reproduction, publication or redistribution of this material without the written agreement of 365 Media Group is strictly forbidden.