Suntory Sungoliath confirmed Monday that George Smith was returning to the club for the 2016-2017 Top League season.
The former Wallaby previously played for Sungoliath from 2011-2014 before heading to Europe.
Last week Smith, who won 111 caps for Australia, was named the Players' Player of the Year following a sterling season with Wasps in the English Premiership.
Earlier in the year he was called up by Eddie Jones to work with the England back row as a specialist breakdown coach.
The 35-year-old flanker will be joined by four other new overseas signings.
Christian Lealiifano (16 caps for Australia) and Nigel Ah Wong both join the side from the Brumbies, Joe Wheeler (three caps for the Maori All Blacks) heads north from the Highlanders and Solomon T-Pole swaps Otago for the Tokyo suburb of Fuchu.
Suntory failed to make the Top 8 in the Top League last season and cleared out its house at the end of the season.
Former head coach Andy Friend has returned to Australia to run the nation's sevens side, Fourie du Preez has retired and Schalk Burger moved back to South Africa and was part of the Stormers team that drew with the Sunwolves last weekend.
Keisuke Sawaki, who was part of Japan's coaching team at last year's Rugby World Cup, is the new boss at Suntory, while Yutaka Nagare has been named club captain in just his second year out of Teikyo University.