The striker has completed a reported move to Upton Park from Mexican side C.F Pachuca, subject to a work permit hearing.
The 24-year-old is thought to have been courted by a number of Premier League clubs in recent weeks following an impressive World Cup showing, but it's The Hammers that have captured the South American's signature.
Valencia scored a goal in each game for Ecuador in Brazil as they narrowly missed out on surpassing expectations, falling just short of progression from Group E.
The Ecuadorian will now join up with fellow forwards Andy Carroll and Mauro Zarate at West Ham, bolstering Sam Allardyce's attacking options, and providing stiff competition for places amongst the first eleven next season.
Not only does the striker arrive on the back of a glittering performance on the world's biggest stage, Valencia also enjoyed a succesful campaign in Mexico's top flight last term, scoring 18 goals in 23 appearances.
After watching Valencia at the World Cup, West Ham winger Stewart Downing has already tipped the new man to be a success at Upton Park;
"He can nick a goal and it is competition for places. It's what we've needed as we didn't have that last season. It will help the manager that he has options and he can bring other people in who can perform straight away."
Sam Allardyce will hope that the 24-year-old can finally provide a goal scoring prowess at West Ham, who have been without a clinical talisman now for far too long.