The Chiefs will announce their full squad for the 2012 season tomorrow, along with the other four New Zealand franchises.
Earlier today Williams hinted at the move tweeting: "I hear hamilton is nice".
NZRU General Manager Professional Rugby Neil Sorensen welcomed Williams' re-commitment as exciting news for New Zealand rugby fans.
"We're delighted that Sonny has chosen to continue playing his rugby in New Zealand next year. He was exciting to watch in Super Rugby this year, and he played an important role in the spectacular Rugby World Cup winning All Blacks side.
"He's a special player who creates some real excitement and interest in the game with his style of rugby. We're looking forward to seeing him create some more excitement in a Chiefs, as well as an All Blacks, jersey next year," Sorensen said.
Chiefs CEO Gary Dawson said: "This is outstanding news for Chiefs fans. He is a world-class athlete who brings with him a unique set of skills and qualities. We are delighted he has chosen to play with us next year and we're looking forward to welcoming him next year."
New Chiefs Coach Dave Rennie said he was thrilled with Williams' signing.
"We're rapt Sonny's joining the Chiefs. He had a very good World Cup and his professionalism and work ethic will have a great influence on what is a very young team," Rennie said.
More to come...
- HERALD ONLINE