have signed Republic of Ireland goalkeeper Darren Randolph on a four-year deal from West Ham United.
Boro have paid the Hammers £5million to sign the 30-year-old.
"I am delighted to get it all signed and completed," Randolph told his new club's official website.
He recently saw Joe Hart arrive at the London Stadium, meaning he was likely to play second fiddle, at best, for the club next season.
"I want to come here and get the club back to where it belongs and I want to be part of something special," he added.