The Canberra Times can reveal Speight has signed a two-year deal to join the Queensland Reds from next season, ending the cult hero's tenure at the Brumbies after almost a decade.

An emotional and genuinely torn Speight told teammates of his impending move before they flew to Japan on Wednesday to prepare for their clash against the Sunwolves this weekend.

Speight, 31, described the decision as the toughest of his life, deciding to put family first to be closer to relatives in Brisbane as he and partner Louise prepare for the birth of their first child.

The Brumbies offered him a one-year deal, but the security of a two-year option at Queensland was too good to turn down. It's understood a switch to rugby league was also on the table and NRL clubs expressed interest.

But Speight is himself still coming to terms with the move, vowing to give Brumbies fans something to cheer about before he leaves the capital.

"I've known for a while, but even telling the boys was still very hard," Speight told The Canberra Times.

"Canberra is all I've known in Australia. I always thought it would be the Brumbies or overseas for me. But in saying that, I'm very grateful for what the Reds have offered.

"I class myself as a Canberran. To leave the Brumbies and to go interstate, it will be tough because Canberra is home."

The Brumbies have three games left in the regular season and are aiming to secure their ticket to the play-offs by staying at the top of the Australian conference.

The club is chasing four consecutive wins this year and has won the past six in a row at Canberra, but rugby fans have deserted stands at venues around Super Rugby.

Brumbies numbers are at record lows and the departure of Speight and David Pocock, who retired earlier this week, leaves the ACT side without two of their most recognisable faces and is a cruel blow to the hopes of rebuilding support.

Cult-hero Speight, who has been at the Brumbies since 2011 and has endeared himself to the community, wants to create some excitement in the charge to the finals.

"Sometimes you don't have it all your way. Just look at Poey, he would have loved to play again. I'm fortunate that I get to do that and hopefully I can leave my mark on the next few weeks," Speight said.

"The next weeks will be special, the memories of being in Canberra and at the Brumbies. Not for me, but my family. I'm very grateful the community has accepted me as one of their own.

"I'd love to finish strongly and push for a finals berth ... I know the crowds are going our way, but I want to give the faithful something to cheer for next year and the next few weeks.

"I'll always be a proud, proud Brumby. Whatever jumper you see me in."

The flying Fijian's shock move to join the Reds will surprise supporters, who have fallen in love with the winger known as "the bro with the fro" after 119 games and 45 tries.

BRUMBIES NEWS

The shock is not at Speight's exit, but rather his destination. Many probably expected him to be targeted by overseas clubs given he had a stint in Ireland last year. But few would have predicted he would end up at another Australian franchise.

"I will be forever grateful for the Brumbies for giving me the chance to play Super Rugby at a club with an unbelievable culture and strong history," Speight said.

"...The Brumbies fans will always hold a special place in my heart.

"I will never forget the kids in who shouted to me when I was on the wing when the ball was on the other side of the field and for those who waited in the middle of winter for an autograph and a chat.

"Whilst I might have a different coloured jersey next year, I can't wait to see those smiles again in the future.

"I am passionate about the game in this country, see a bright future for Australian Rugby and still have ambitions to contribute at the national level.

"This was the toughest decision I have ever made but discussions with my partner Louise and as an expecting parent for the first time, we thought that a longer-term arrangement and the chance to be around family was the right choice for us all. Regardless of what that future may hold, I am happy and extremely proud to be a Brumby for life."

The reality is the end of a World Cup four-year cycle always creates contract uncertainty.

The Brumbies will be without Speight, Pocock, Sam Carter and Rory Arnold next season, while captain Christian Lealiifano is weighing up offers from overseas teams.

But the club has made significant moves to secure the bulk of their roster, re-signing Lachlan McCaffrey this week to join Allan Alaalatoa, Scott Sio, Tom Banks, Tom Cusack, Rob Valetini and Darcy Swain in recommitting.

Outside centre Tevita Kuridrani is close to finalising a deal to stay in Canberra while Matt Lucas is expected to extend his contract and former scrumhalf Nic White is in negotiations to return to the Brumbies next year.

Speight will finish as the most capped winger in Brumbies history and third on the club's all-time try-scoring list. He has also played 19 Tests for the Wallabies.

But Speight's love of the city extended beyond the Brumbies walls. He wanted to tell the Gungahlin Eagles of his decision before it became public because he had so much passion for the club he was once named clubman of the year despite not playing a game. He has also been an ambassador for Lifeline Canberra.

Speight has returned to his best form in recent weeks, finding his attacking spark to help the Brumbies win their past three games in a row.

"I think [Speight's] benefiting off the good work of those inside him both in attack and defence," said Brumbies coach Dan McKellar.

"Our backs have clicked. Peter Hewat has done a really good job there ... Speighty is benefiting off the back off that. He's in a really good place, he's happy."

He will be crucial to the club's hopes of making the finals, starting with a clash against the Japan Sunwolves in Tokyo on Saturday.

But the race to the play-offs will finish with a showdown with his future Reds teammates when the Brumbies play Queensland in the last game of the regular season.

The top of the Australian conference Brumbies will play the Sunwolves, the Reds and the NSW Waratahs in their last three games.

They are one point ahead of the Melbourne Rebels, with Australia's top team to be guaranteed a spot in the play-offs.

SUPER RUGBY ROUND 16

Saturday: Japan Sunwolves v ACT Brumbies at Tokyo, 3.15pm.