Goalkeeper Darren Randolph has signed a new four-year contract ahead of West Ham's move to the Olympic Stadium.
Randolph, 29, joined the Hammers from Birmingham last summer and featured in six Premier League games last term.
Randolph told West Ham's official website: "I've had a good first year at West Ham and this is another positive thing to happen to me at the end of a good first season and a good summer with Ireland.
"It has gone better than I could have ever expected at West Ham since I joined last summer, playing as many games as I did and then starting for Ireland in the play-off and at Euro 2016.
"Signing a new contract means I want to stay here for a long time and be part of what is going on with the club, moving into a new stadium and a new training ground - it's all very positive and exciting."
Randolph will compete with Spanish goalkeeper Adrian for the right to wear the gloves in Slaven Bilic's starting XI.
"I spoke to the manager and I know we both have the opportunity to work towards that number-one position, which was part of the reason I was happy to sign a new contract," Randolph added.
"It is good to know I have the manager's backing, and it certainly helps my confidence to know he believes in what I can do."
Randolph made four appearances at Euro 2016 as Martin O'Neill's Republic of Ireland team reached the round-of-16.