The former Hull striker becomes Paolo Di Canio's sixth summer signing at the Stadium of Light as he continues to overhaul a squad which narrowly avoided relegation
Sunderland have completed the signing of AZ striker Jozy Altidore, both clubs have confirmed.
The United States international has formalised his move to the Stadium of Light from the Eredivisie side on a four-year deal after completing a medical.
He becomes new boss Paolo Di Canio's latest signing ahead of the new Premier League season, joining fellow new boys Duncan Watmore, David Moberg Karlsson, Cabral, Modibo Diakite, Valentin Roberge and Vito Mannone.
A statement on the club's official website read: "Sunderland AFC have confirmed the signing of US striker Jozy Altidore from Dutch side AZ Alkmaar.
"(He) is set to join up with Head Coach Paolo Di Canio and his new team mates at their training camp in Italy on Tuesday."
Altidore moves for an undisclosed fee, reported to be in the region of £8.5 million, with the deal bringing to an end Di Canio's lengthy pursuit of a player who was identified as one of his main close-season transfer targets.
The 23-year-old has excelled for AZ since joining the club from Villarreal in 2011, scoring 38 goals in 67 appearances, and helping the club to qualify for the UEFA Europa League last term.
That form has now prompted Sunderland to hand the American - who began his career in Major League Soccer with New York Red Bulls - another chance to impress in the Premier League, where he spent time on loan in 2009-10 with Hull City, scoring one goal in 28 league appearances.