The Rabbitohs have negotiated an undisclosed release fee and also a clause that enables them the first and last offer on Burgess’ services, should he return to rugby league in the future.
Burgess said: “I’m happy this has all been sorted out before the start of the season so that I can concentrate on my game and the team without any other things in the way.
“An opportunity presented itself to head back home to England and to pursue a chance to represent my country in two different sports.
“With 2015 being a Rugby World Cup, it was an opportunity I had to pursue and I thank the Rabbitohs for allowing me to make this move and start the next chapter in my sporting career.
“But all of that starts next season.
“We have a great opportunity in front of us now as a group and I’ll be doing my best every week to help us win each game and hopefully improve on what we’ve been able to achieve in the past two seasons.”
The Dewsbury-born forward has been with Souths since 2010, after previously playing 88 times for Bradford.