Du Preez will make his first appearance for the Springboks since the 2011 World Cup after being recalled for the clash in Cape Town, which will be live on Sky Sports 2 HD.
That means the 30-year-old scrum-half, who plays in Japan for Suntory Sungoliath, will link up with his former Bulls team-mate Steyn at Newlands.
"Fourie brings something extra that no other scrum-half can," said Steyn. "The way he reads and controls the game makes such a difference to the fly-half.
The inclusion of Adriaan Strauss is the only other changes to the Boks line-up and the Cheetahs hooker is expecting a tough clash - despite the Wallabies losing the home fixture 38-12.
"That defeat would have stung them and they will be supremely motivated," said Strauss. "They will be looking to up their game, especially the forwards.
Rugby Championship weekend preview
"But we are also positive and have been working hard on our scrumming - an area that has gone well for us this season."
Bulk
The Wallabies have lost four of their five games in this season's Rugby Championship, however coach Ewen McKenzie remains upbeat over his side's chances.
"It is not like the Springboks were way out of our league," he said.
"We did not get to the game plan we wanted last time so we have stuff up our sleeve.
"You need to fight fire with fire to some extent against South Africa and it is pretty clear that we have brought in extra bulk."
Tevita Kuridrani, Joe Tomane and skipper James Horwill all come into the starting XV for the clash, with Adam Ashley-Cooper moving to the wing.
Sitaleki Timani and Benn Robinson have also been added to the bench as Australia look to snap a five-match losing streak in Cape Town.
South Africa: 15 Zane Kirchner, 14 Willie le Roux, 13 JJ Engelbrecht, 12 Jean de Villiers (capt), 11 Bryan Habana, 10 Morne Steyn, 9 Fourie du Preez, 8 Duane Vermeulen, 7 Willem Alberts, 6 Francois Louw, 5 Flip van der Merwe, 4 Eben Etzebeth, 3 Jannie du Plessis, 2 Adriaan Strauss, 1 Tendai Mtawarira.
Replacements: 16 Bismarck du Plessis, 17 Gurthro Steenkamp, 18 Coenie Oosthuizen, 19 Juandre Kruger, 20 Siya Kolisi, 21 Ruan Pienaar, 22 Patrick Lambie, 23 Jan Serfontein
Australia: 15 Israel Folau, 14 Adam Ashley-Cooper, 13 Tevita Kuridrani, 12 Christian Lealiifano, 11 Joe Tomane, 10 Quade Cooper, 9 Nic White, 8 Ben Mowen, 7 Michael Hooper, 6 Scott Fardy, 5 James Horwill, 4 Rob Simmons, 3 Ben Alexander, 2 Stephen Moore, 1 James Slipper.
Replacements: 16 Saia Faingaa, 17 Benn Robinson, 18 Sekope Kepu, 19 Sitaleki Timani, 20 Ben McCalman, 21 Will Genia, 22 Matt Toomua, 23 Chris Faeuai-Sautia.
South Africa v Australia will be live on Sky Sports 2 HD from 3.15pm or you can watch all the action unfold with a 24-hour Sky Sports Day Pass from NOW TV. For more information visit click here
Source : http://www1.skysports.com/rugby-union/news/15175/8943598/south-africa-v-australia-rugby-championship-match-preview