Canada international Alphonso Davies completed his first training session at FC Bayern Munich on Wednesday and is eligible to play for the club from January.
Davies, 18, signed for Bayern from Vancouver Whitecaps in July for an initial fee of €11.5 million, which could reach €18.75m with add-ons, and completed the MLS season before moving to Germany.
Having arrived in Munich earlier this week, the winger said he was looking forward to starting work with the Bundesliga champions.
"As a kid, I dreamed of being part of such a big club. Now I am and it's unbelievable," he told the Bayern website.
"I'm very excited and looking forward to my time here. I want to prove myself every day in training and work hard."
Sporting director Hasan Salihamidzic said Bayern were "excited" to welcome the winger, who could be the only addition to their squad this winter.
"I am sure he'll develop here at Bayern and help us. I wish him the best of luck and success," Salihamidzic added.