Renato Sanches has completed the necessary paperwork while away with Portugal and will link up with his new team-mates upon his return from international duty.
Swansea boss, Paul Clement worked with the 20-year-old midfielder during his six-month stint as assistant manager at the Allianz Arena last year before his switch to the Liberty.
“I’m delighted to secure his services,’’ declared Clement. “He is a player I know well having worked with him for six months at Bayern Munich before my own move to Swansea.
“Having moved from Benfica to Bayern Munich, he has not played as much as he would have liked. But this move to Swansea and the Premier League will provide him with a real positive development experience.
“As a player, he is a dynamic, powerful central midfielder who I believe has all the attributes to suit the Premier League.’’
“I first contacted Karl-Heinz Rummenigge, who is chief executive at Bayern Munich, early in the summer,’’ explained Clement.
“They felt Swansea was a place he could be coached and developed – and where he would play more regularly.
“I’d like to thank Karl and Carlo for showing their trust in the club and myself as a coach by allowing Sanches to come.
“I’m sure he will get a warm Welsh welcome next week and we wish him great success with this.’’
Sanches joined Bayern Munich last season from Benfica for £27.5 million after impressing in Portugal’s successful Euro 2016 campaign, in which he was named the best young player of the tournament and was also the recipient of the journalist-nominated Golden Boy award.
He made 26 appearances for the German giants last season, helping them lift the Bundesliga title.