Veteran spin great Ravichandran Ashwin on Thursday joined Sydney Thunder as the first Indian men's international to feature in Australia's Big Bash League.

The Board of Control for Cricket in India (BCCI) does not allow any current player in Indian international or domestic cricket to feature in overseas leagues.

But Ashwin retired in December during India's Test tour of Australia and quit the Indian Premier League in August, freeing him up to be "an explorer of the game around various leagues".

"Thunder were crystal clear about how they'd use me and brave enough to back it," said the 39-year-old in a statement.

"My conversations with the leadership were excellent and we're fully aligned on my role."

Ashwin will be available from early January, joining David Warner as Thunder bid to make back-to-back BBL finals.

"I love how Dave Warner plays the game and it's always better when your leader shares your mindset," he added.

Ashwin, who played for five IPL franchises, finished his India career with 537 wickets in 106 Tests at an average of 24.00.

He also played 116 one-day and 65 Twenty20 internationals.

"From the first time we spoke, Ashwin impressed everyone at the Thunder with his passion, desire to win and understanding of what makes our club special," said Thunder general manager Trent Copeland.

"He will bring an injection of fresh energy and world-class bowling mid-tournament while his presence as a leader and mentor will be invaluable for our young players."

The BBL gets under way on December 14.