The 28-year-old centre, who is currently abroad with the Munster squad on a warm-weather camp, said: "My decision to return to South Africa is solely determined by a desire to put myself in contention for the Sprinboks' 2011 Rugby World Cup squad.
"I feel this is perhaps my last opportunity to represents my country at the Rugby World Cup and after consultation with SARU, it has become clear that to qualify for selection players must be playing their rugby in South Africa in the season leading up to the competition.
"I'm thoroughly enjoying my time here in Munster and I think it would be fair to say that had the Rugby World Cup not been a factor, then I would be remaining for at least the next two seasons.
"I would not rule out returning here after the next World Cup either, if the opportunity arose."
He added: "For now though, my entire focus is on the Magners League and Heineken Cup campaigns.
"There's a lot of rugby to be played yet in the red shirt and I'm looking forward immensely to continuing my involvement with a great squad."
In announcing the news, Munster Rugby Chief Executive Garrett Fitzgerald said: "Jean missed the 2003 World Cup through injury and played just 40 minutes in 2007. So his desire to represent his country in the most prestigious rugby competition is totally understandable.
"Jean made us aware of this scenario before he joined us last September. He has been a hugely positive addition to the squad this season. His influence has grown and continues to grow as he becomes more and more comfortable within the squad.
"While he will be a major loss, we fully respect his ambition and he will leave us at the end of the season with our very best wishes."