Having first represented Scotland at U16 level, Brown made his full international debut in 2005 and has since gone on to win 30 caps for Scotland; he was part of his country's 2007 World Cup squad. Brown had been a mainstay of the Glasgow Warriors side.
Brendan Venter, Director of Rugby, said: "We are delighted Kelly has decided to join our club. He is a proven international who, at the age of 26, is in his prime. On the field, he is precisely the kind of big, dominant loose forward we have been seeking, and off the field, he is precisely the type of outstanding character who fits our culture."
