Francois Hougaard will play for the Canon Eagles next season having signed a deal to join after the World Cup.
The Springbok scrum-half or winger had been rumoured to be a target for several clubs in the northern hemisphere, but his first stop will be in Japan in the Top League.
Currently at the Bulls, Hougaard will be joined by Sharks-bound full-back Willie le Roux, who will also play for the Eagles before his move to Durban next season.
"I'm really glad I can become a member of the Canon Eagles after the World Cup," said Hougaard.
"I've watched the game highlights of the Top League over the past two years and I saw they were technically very high, and I could feel a strong passion.
"I'm looking forward to being able to compete in this high level environment. I'll give out my best for Eagles to win the Top League."
It is not yet clear whether Hougaard will return to South Africa to play in Super Rugby next season, or whether he will then move to Europe, with Exeter and Leicester among those clubs reportedly chasing his signature.