Bayer Leverkusen signed the highly rated 16-year-old grandson of former West Germany international Uwe Seeler from Bundesliga rival Hamburger SV on Friday.
Midfielder Levin Oeztunali, a Germany youth international, agreed to join the club from next season with a contract through June 2018, Leverkusen said.
''Many young German players started their careers with Bayer Leverkusen. I have a very good feeling about my decision and am looking forward to a great challenge at a top club,'' Oeztunali told Leverkusen's website.
The 76-year-old Seeler, who played 72 times for West Germany, is still considered an idol at Hamburg, and Oeztunali's departure will come as a blow for the club.
Hamburg sporting director Frank Arnesen told German daily Bild that the club made a huge offer to hold onto its prospect.
''Levin could have trained with the first team from the summer,'' Arnesen said. ''From a financial point of view there was never such a good offer made to a youth player at HSV.''