Bayern Munich completed the signing of Lucas Hernandez from Atletico Madrid for a fee of €80million.
The versatile defender had emerged as a target towards the end of last year, with Bayern not making any secret of its desire to bring him in.
A January move was not possible, and Atletico attempted to ward off Bayern's interest by offering him a new contract at the Wanda Metropolitano.
However, Lucas' head had already been turned and he will join up with the Bavarian giant at the end of the season.
Bayern is paying almost double the previous Bundesliga transfer record of £35m (€41.5m), which it shelled out on Corentin Tolisso, but Lucas is not quite the most expensive defender of all time.
Hernandez thanked Atletico Madrid after turning down a new contract to seal a switch to Bayern and start a "new challenge" in Germany.
The 23-year-old refused an offer of an extension at the Wanda Metropolitano to sign a five-year deal in Bavaria but stated it was difficult to depart after an "unforgettable" spell at the club. However, Lucas is confident he has made the right choice.
"This is the most difficult and important decision I have had to make in my sports career," he said in an Atleti statement.
"Atletico mean a lot to me because this is where I grew up as a player, as a person and I have become the player that I am. It has been difficult for me to say no to Atletico, but my decision is to undertake a new challenge at Bayern Munich.
"I want to thank all the Atletico officials, coaches, team-mates and fans for these 12 incredible and unforgettable years in which I have been part of the club.
"Atletico will always be in my heart."
In a release issued by Bayern, Lucas added: "Today is a very important day in my football career. Bayern Munich is one of the best clubs in Europe and the world. I am proud to be able to fight for all titles for Bayern in the future."
Lucas made 110 appearances for Atleti and was part of the side that won the Europa League last term and reached the Champions League final in 2015-16.
He came into the first team the season after their incredible 2013-14 campaign in which Diego Simeone's men won LaLiga and lost to rivals Real Madrid in the Champions League final.
Lucas played all seven matches for France as they won the 2018 World Cup and will link up with international team-mates Benjamin Pavard, Kingsley Coman and Corentin Tolisso at Bayern next season.