"Bryn is a huge addition to our squad for next season," said London Irish head coach Toby Booth.
"His physical presence and his capabilities around the field will hold us in good stead for the 2011/12 campaign. The experiences Bryn will bring from playing for the Hurricanes and All Blacks will no doubt rub off on the young players we have coming through in the second row position."
Bryn Evans, who will join London Irish in September, added: "I am looking forward to testing myself against a different opposition in a different club competition. The chance to play in the Heineken Cup against the best teams in Europe is also a very exciting prospect. There are some great players at London Irish and I look forward to playing alongside them all when I join."