Currently with the Wallabies in New Zealand, preparing for the Bledisloe Cup, Powell fills a vacancy left in Melbourne with the departure of Ryan Louwrens back to Japan.

While Powell is the Super Rugby club's first signing for 2021, the Rebels have confirmed a large turnover of players with eight heading to Japan.

The club's most capped player, Tom English, and veteran hooker Anaru Rangi, who both missed the Super Rugby AU season, are among the departures as well as winger Andrew Kellaway, five-eighth Andrew Deegan, lock Michael Stolberg and youngsters Esei Haangana and Semisi Topou.

Wallabies lock Matt Philip will play with French Top 14 side for the 2020-21 season.

Powell and fellow Wallabies halfback Nic White have both been tussling for the starting jersey at the Brumbies and the 26-year-old will be guaranteed of more game time with the Rebels.

With 73 appearances for the Brumbies after making his debut in 2015, Powell started for the Canberra team in last month's Super Rugby AU title win over Queensland.

"To play one time for the club was incredible, but to play 73 times and go out winning a trophy is a special feeling and I've enjoyed every minute of my time with the club," Powell said in a statement.

"I'm happy to be continuing my career in Australia and I'm looking forward to a new challenge in Melbourne."

Melbourne coach Dave Wessels said he was looking forward to working with Powell.

"We've obviously played against Joe many times over the years and know just what a competitor he is," Wessels said.

"Aside from the skill and intensity he brings on the field, it's obvious that he's a good team man. He's a great fit for Melbourne."

Australian Associated Press