Christoper Vivell has joined Chelsea as the Premier League club's new technical director.
Vivell was dismissed from a similar role at Bundesliga side RB Leipzig in October, amid reports Chelsea were attempting to bring the 36-year-old to west London.
The German has now made the move to Stamford Bridge, with Chelsea confirming his appointment on Wednesday.
"Chelsea are building the most exciting project in global football and I'm extremely proud to be joining the club," said Vivell.
"There is so much potential for the club to continue to succeed, develop and grow. Under the new ownership, Graham Potter and the broader sporting team, there is a clear and sustainable philosophy underpinned by performance analysis, data and innovation, and I am looking forward to playing a part in that."
Chelsea lost four of their last five games prior to the World Cup break, with Potter's team losing three consecutive Premier League matches in that run.
That poor form had seen some suggestions of pressure building on Potter, but co-owner and chairman Todd Boehly believes Vivell will play a vital role in supporting the head coach.
"We are delighted that Christopher is taking up this important leadership role at the club," Boehly said. "His work in Germany and Austria speaks for itself. We are confident he will continue on his impressive trajectory here at Chelsea.
"He will provide important support to Graham and the ownership group and play a vital part in advancing our overall vision for the club."
Chelsea restart their campaign on Tuesday with a home match against Bournemouth.