The Texan won Tiger Woods' charity event in California the week after the Australian Open and also won two regular US PGA Tour events in his sensational run this year.
"I am absolutely thrilled to return to Sydney," said Spieth in a Golf Australia statement.
"It has been an amazing six months since I left Australia.
"I can't wait to come back and hopefully defend the Stonehaven Cup."
Spieth was world No.11 when he won the Australian Open but he is now closing in fast on Rory McIlroy for the No.1 spot.
Australian Open tournament director Trevor Herden was understandably delighted to have Spieth signed up.
"Jordan was a massive hit at The Australian last year - nobody who saw him play will forget his final round, in particular," Herden said.
"But more than just play good golf Jordan has been a tremendous ambassador for the tournament and has sung its praises in some pretty lofty places since he left, including at Augusta after he won The Masters."
-AAP