Jarrad Butler will leave Canberra for Connacht at the end of 2017.
The 70-cap flanker, who started his Super Rugby career at the Reds before making the move south, has signed a deal with the Pro12 club for the 2018 season.
Butler has been a regular fixture in the Brumbies' best 23 since joining the club in 2014 and the Brumbies will miss his tireless work rate, strong carries and formidable breakdown work.
"I am extremely excited to be given this opportunity to join Connacht,” Butler said.
“I've thoroughly enjoyed my time at the Brumbies, however this new set of challenges on the other side of the world is something that I can't wait to embrace.
“I look forward to being a part of this proud club, to meeting the supportive fans and community, and most importantly doing everything I can to help Connacht be successful.
“I'd like to thank the whole team of Brumbies staff, coaches, and especially the players for their support, friendships, and lasting memories during my time in Canberra.
"You've made these last four years the best of my life."Connacht Rugby CEO Willie Ruane was delighted to announce the 25-year-old as a new addition for 2018.
"We’re delighted to be signing someone of Jarrad’s rugby ability and believe he will be a big addition to our squad," he said.
“As a backrower who is equally adept in all three positions, he brings a huge amount of versatility to the team.
“At a young age, Jarrad has already gained a great deal of experience as a leader in a highly professional environment and we look forward to welcoming him to Connacht Rugby at the conclusion of the Super Rugby season.”