West Ham have signed Canadian defender Doneil Henry from Cypriot side Apollon Limassol for an undisclosed fee.
The 21-year-old centre-back joins the Hammers on a long-term contract after spending two periods training with the club in recent months.
Henry was recommended to West Ham manager Sam Allardyce by former Blackburn and New Zealand captain Ryan Nelsen, his former coach at Toronto FC.
Henry, who was the first player to graduate from Toronto's academy, told West Ham's official website: "It feels good to be given the opportunity to come and train and see what it's like to be part of a Premier League team and I just want to get started and get into the team real soon.
"I had a really good relationship with Ryan Nelsen and I always wanted to see what it was like to play at another level, the highest level, and I got the opportunity to come over here.
"Since then, I was just hoping to come back and, now it's happened.
"I'm 21 and I want to get a role with the team, keep my head down and take my opportunity when I can. I love a tackle and I just want to defend hard."
Henry has 14 caps for Canada having established himself as a regular starter over the past couple of years and Allardyce expects him to challenge for a spot in the team this season.
The Hammers boss said: "Ryan was my captain at Blackburn for a couple of years and he rang us and told us about Doneil.
"With a little coaching from us and work in terms of how to defend in the Premier League, Ryan says he has all the attributes to be a good player.
"We have invested in him for the near future, so we do hope he can make some sort of appearance this season if he settles in and does as well as Ryan thinks he will. If not, we hope he is certainly one for the future."