Gear, who follows fellow All Blacks Sam Tuitupou and Greg Rawlinson, Fiji international Netani Talei, Samoa star Loki Crichton and front row giant Shaun Ruwers as the new arrivals at Sixways, added: "I know this is the right club for me and my family at the right time in my career.
"The Warriors have shown their burning desire to move forward in recent months by signing a number of world-class players, including Sam (Tuitupou) and Greg (Rawlinson) who I both know well from Super 14 rugby and the All Blacks. I'm looking forward to coming over with them and making a real impact at Sixways.
"I believe all the ingredients are now at the club so that I can be part of a successful Warriors side that will challenge for honours in the English game in the future."
Worcester director of rugby Mike Ruddock said: "It's been a major goal of ours to recruit as strongly as possible during the off season for a number of reasons.
"We wanted to make a statement about our ambition as a club and about the future of Worcester Warriors that we believe will be a very positive one.
"We also want to try to play an exciting brand of rugby that encourages players to express themselves and creates interest amongst our supporters.
"I believe in the signing of Rico we've certainly achieved both those factors and we're hoping that such a quality player will act as a catalyst for a progressive brand of rugby.
"Rico is one of the best finishers in the game and he has got the pace to finish of the any chances that we are looking to create for him."