West Ham swoop for Ecuador's Enner Valencia
Ecuador forward Enner Valencia celebrates after scoring during a Group E match between Honduras and Ecuador in Curitiba during the 2014 World Cup on June 20, 2014 - by Christophe Simon
West Ham announced on their official website that they had agreed an undisclosed fee with Pachuca and that Valencia, 25, will sign a five-year contract at Upton Park.
Reports in England suggest the transfer fee will come close to the club record sum of £15 million (€18.9 million) paid for striker Andy Carroll last summer.
Formerly of Ecuadorean side Emelec, Valencia only joined Pachuca in January this year but his excellent performances at the World Cup generated widespread interest from clubs in Europe.
Valencia scored all three of Ecuador's goals in Brazil, including a brace in a 2-1 victory against Honduras, but he could not prevent the South American nation from being eliminated in the group stage.
He is West Ham's fifth summer signing following the captures of Argentine forward Mauro Zarate, Senegal defender Cheikhou Kouyate, left-back Aaron Cresswell and youngster Diego Poyet.