Former Western Bulldogs defender and Collingwood assistant Matthew Boyd has joined Fremantle's coaching ranks under Justin Longmuir.

The Dockers announced the signing on Wednesday, with Boyd re-joining Longmuir after the pair worked alongside each other for two seasons with the Magpies.

Boyd, premiership winner and three-time All-Australian and best and fairest winner with the Bulldogs will work with the Fremantle defenders as an assistant coach.

Longmuir commended Boyd's professionalism and welcomed him to the Dockers.

โ€œMatthew is a person of really high character and Iโ€™m looking forward to seeing him get around our young players,โ€ Longmuir said.

โ€œI thought he was a really driven young coach when he was at Collingwood and he really helped me a lot. I also look forward to helping him develop his coaching career.

โ€œHeโ€™s a good relationship builder. Heโ€™s very good at working with players one-on-one and he understands what it takes to be a professional footballer for a long time.

โ€œHeโ€™s done a lot in footy, but most of all, heโ€™s a good coach and I know heโ€™ll impart a lot of his knowledge and experience on our players and make the team better.โ€

Boyd revealed Longmuir was a major factor in moving to Fremantle.

โ€œIโ€™m really excited to be a part of the culture thatโ€™s really building at Fremantle,โ€ Boyd said.

โ€œA big part of my decision to come over was clearly my relationship with Justin. Heโ€™s been an amazing mentor to me in the short coaching career that Iโ€™ve had so far and this was an opportunity to continue to learn from him.

โ€œItโ€™s an exciting time to be a part of the Fremantle Dockers after a really positive year and I know that the footy club is heading in the right direction.

โ€œTo be a part of that at the start of a really exciting journey was something that appealed to me.โ€

Boyd won the 2016 premiership with Dockers defender Joel Hamling and touched on the exciting prospect of joining a youthful coaching group.

โ€œI think footy is the hardest game in the world and your ability to empathise and relate to what the players are going through is important,โ€ Boyd said.

โ€œItโ€™s about being able to teach and educate so the right message is getting through and the players are understanding as best as possible.

โ€œWhile itโ€™s obviously great to have experience, youth brings a whole lot of energy and vitality for the job and Iโ€™ll certainly bring my energy to the role as best as I can.

โ€œIโ€™m really excited to work with the young and emerging backline and I canโ€™t wait to get over there and meet the boys and try and help them as best as I can.โ€