Brazilian playmaker Diego has completed his "dream" move to Juventus from Werder Bremen, for a fee of €24.5m.
The 24-year-old, who helped steer Werder to the UEFA Cup and German Cup finals this season, had two years left on his contract with the Bundesliga side but had made it clear that he wanted a new challenge.
Diego's performances also attracted the interest of German giants Bayern Munich but after signing a five-year contract with the Bianconeri he said: "I'm enthusiastic about Juventus and proud to become part of such a prestigious club, which I have dreamed about since I was a child."
The Brazil international, who joined Werder from Porto in 2006, added: "After the experiences in Portugal and in the Bundesliga I will be able to measure up to football of a very high level in a difficult and very competitive championship.
"It's the right time in my career to make such an important step and I'm convinced that with Juventus I'll achieve great results."
Diego's arrival is aimed at filling the gap created by Pavel Nedved's expected retirement. Juve also hope Diego can spur them to success in the Champions League and on the home front next season. Claudio Ranieri's failure to do so cost the coach his job last week.
Juventus, who are currently in the hands of caretaker boss Ciro Ferrara, also have a deal to bring Italy captain Fabio Cannavaro back from Real Madrid despite widespread supporter opposition.
The 35-year-old centre back, soon out of contract at Real, left for Spain in 2006 when Juve were demoted for match-fixing, while other top players such as Alessandro Del Piero and Gianluigi Buffon stuck with the club for their season in the second tier.