Former All Black and Blues scrumhalf has signed to play Super Rugby in Australia for the Western Force from next season.
Mathewson, who has spent the past three seasons representing the Blues, will join the West Australian side as its marquee international signing for 2013.
The probing scrumhalf was internationally capped four times for the Kiwis in 2010 and has amassed 83 Super Rugby caps since making his debut for the Hurricanes in 2007 against the Reds.
The 26-year-old, who played every match for the Blues in 2012, was named New Zealand's Super Rugby Player of the Year in 2010, leading to his Test debut off the bench in the All Blacks' 20-10 win over Australia in Christchurch that season.
Mathewson, who scored the match-winning try for Auckland in their 36-29 ITM Cup season opener against Hawkes Bay on Thursday, says he's thrilled to be linking with the Western Force.
"This is an excellent opportunity for me and one I'm really looking forward to," he said. "I've really enjoyed my time at the Blues but this is a chance for me to challenge myself in a new environment, play a different style of rugby and it's a prospect that really excites me.
"The Force are entering a really exciting period with a new coach coming in, and it's a great chance to be part of building something special and for this playing group to leave a significant legacy at the club.
"They [the Force] obviously experienced a tough season this year, but sides have shown that things can be turned around quickly and from my discussions with the club things are certainly heading in the right direction.
"I'm really looking forward to getting over there, settling into Perth with my partner and getting stuck in to do my bit towards the team's success next season."
Mathewson spent three seasons with the Hurricanes (2007-2009) before linking with the Blues, having previously represented New Zealand Under 21's (2006).
Incoming Western Force coach Michael Foley says Mathewson will help bring balance to his squad for 2013.
"We're very pleased to welcome Alby to the Western Force as our marquee player for next season," he said.
"As we prepare to relaunch the side, we've focused on recruiting some of the best up-and-coming talent. Having Alby join us in a key position like scrumhalf will not only add to our performance next season, but also ensure we're able to develop our young talent to its fullest potential.
"Alby has a good all-round game with attacking skills that allow him to identify and exploit opportunities in the defensive line. Our goal is to play up-tempo rugby that our players and supporters enjoy, and it's a brand of rugby that will suit Alby's skills.
"Alby's been a stalwart at this level for the past six years and will, along with Brett Sheehan, provide us with two very experienced options at scrumhalf in 2013."
Charles Mountifield, General Manager Rugby Operations (Australia) of the Essentially Group said Mathewson was keen to continue his rugby career with the Western Force.
"Alby has established himself as a top scrumhalf in New Zealand's competitive rugby environment for the past six seasons," he said. "He's a player that's made the most of an opportunity that's been presented to him throughout his career, and he's certainly looking to repay this opportunity with the Force as their marquee signing for 2013."
Name: Alby Mathewson
Representative Rugby: 2008 and 2010 All Blacks, 2009 Junior All Blacks, 2006 New Zealand Under 21