The New Zealander is to join Cardiff Blues next summer
Ulster Number 8 Nick Williams is to leave the province at the end of the season it has been announced.
The 32-year-old is to stay in the Pro12. He joins Cardiff Blues on a long-term contract.
It is the second blow for the provinces in two days after it was announced that Ben Te'o will leave Leinster in the summer. He will move to Worcester in the English Premiership.
Williams joined Ulster in 2012. He was named the Pro12 Player of the Season at the end of his first first year with the province. He has made 67 appearances for the Province, scoring 13 tries.
Commenting on the move, Williams said: "I've thoroughly enjoyed my time in Belfast. The Ulster people are special and the supporters have always been so good to me. My daughter was born in Ireland so it will always be a special place for our family."
"Rest assured, I'll be giving everything for the team until the end of this season. We have set our targets over the next five months and I want to play my part in us achieving them.”