Enner Valencia has been granted a work permit in order to complete his transfer from Pachuca to West Ham.
Valencia, 25, agreed to join the Hammers after scoring three goals for Ecuador at the 2014 World Cup and following a hearing at Wembley Stadium on Tuesday he will join the squad ahead of the new Premier League season.
He told the club's official website: "I really appreciate the welcome I've been given and I'm excited to be here.
"I've already watched and read a lot about the club to learn about it -- I know the fans are really passionate and I'm really glad to have signed.
"The World Cup was a good tournament for me personally, I scored three times and for my first World Cup it was a good experience, but I hope my next one is better for me and the team.
"Of course, the World Cup gives me confidence to come to Europe and I want to take and advance with this opportunity that West Ham have given to me.
"The Premier League is the top league and I have followed it in Mexico. Obviously my countryman Antonio Valencia has played here for a long time so it's a big step for me to come here from Mexico and I hope I can be as successful as Antonio.
"It's exciting to be here in England and London. I want to repay the club in my performances for what they are investing in me and I'm really looking forward to it."
Valencia scored against England for Ecuador during a 2-2 draw in Miami prior to the World Cup and he hopes to continue that form against English defenders.
He added: "For me, scoring against England, one of the big teams in the world, before the World Cup was important for me. Hopefully I can score again against those defenders!
"I scored many goals as a striker. I'm fast, and I try to continue like that because I know the goals brought me to West Ham."