Leeds have signed former West Ham forward Sonny Perkins, 18, on a three-year contract.
West Ham are entitled to compensation for Perkins and a fee will be set by a tribunal if they and Leeds cannot reach a deal.
The England youth international attracted the attention of a number of clubs after it became clear he would not sign a new deal with the east London club.
Leeds beat off competition from the likes of Aston Villa and Tottenham to sign the young forward.
Perkins will initially start with the Under-21 squad for the forthcoming season, a statement from Leeds read.