Ben Barba will play for Toulon for the remainder of the 2016-17 Top 14 season, according to the French club's website.
The glamour club, which recently confirmed the imminent departure of Toulon favourite Matt Giteau, announced Barba would be joining the team as soon as next week on a short-term contract.
Barba's future had been unclear in recent months, with the Sharks fullback testing positive to cocaine after Cronulla's drought-breaking NRL premiership.
Despite initially releasing the 27-year-old, Sharks moved to re-sign him only a fortnight ago, with the NRL to review and approve the contract.
La star Australienne de rugby à XIII, Ben Barba s'engage avec le RCT pour cette fin de saison : https://t.co/OhebNiY9L4— RCT - RC Toulon (@RCTofficiel) January 31, 2017
Any return to NRL would involve a 12-week ban, but the league has no jurisdiction on other codes or competitions outside of Australia, so Barba would be free to play immediately for Toulon.
The Top 14 is currently on break for the Six Nations but will resume in mid-February, finishing in June, when Barba would be free to return to the Sharks if his one-year deal is approved.
There had been rumours the enigmatic back would switch to rugby, though it was thought Japan would be his destination.
Barba is the second high-profile NRL player to join Toulon in recent months, with controversial Parramatta flyer Semi Radradra set to make the switch at the end of the 2017 NRL season.