Ousmane Dembele has officially put pen to paper on a five-year contract at Barcelona after completing his medical, the club have confirmed.
The 20-year-old arrives for an initial fee of £96.8m, potentially rising to £135.5m, and becomes the second most expensive player of all time.
Dembele was filmed alongside the club's president Josep Maria Bartomeu on Monday signing the contract, which has a release clause of £369.6m.
"I'm really pleased to form part of the Barca family," Dembele said after signing his contract. "I have always wanted to play for Barca since I was a kid. I watched all their matches.
"I'm really happy to now be part of the best club in the world with the best players in the world. I hope to win lots of trophies and titles here. I'm hoping forward to a good year, a successful year and looking forward to playing here in this stadium.
"Visca Barca, visca Catalunya."
Dortmund had rejected a bid for the youngster earlier this month, before he missed training in protest at the club's decision.
The Bundesliga club said they had rejected the offer because it "did not correspond to the extraordinary footballing and additional value of the player and the present economic situation of the European transfer market."
A fee was agreed last week, and Dortmund claimed that the payment of add-ons "was agreed up to a maximum total amount of approximately 40% of the fixed transfer fee."
Dembele scored 10 goals and provided 21 assists for Dortmund last season, as they finished third in the Bundesliga and won the German Cup.