The inclusion of the exciting Gelant on the left wing is one of five changes to the starting line-up announced by Springbok coach Allister Coetzee.
There are four changes amongst the forwards.
Steven Kitshoff replaces experienced prop Tendai Mtawarira who is suffering with a groin injury and is not available for selection.
Siya Kolisi replaces Bath’s Francois Louw on the flank while Du Preez takes over from Duane Vermeulen at No 8.
“We expect another gruelling contest against a strong Welsh team,” said Coetzee.
“It is another opportunity for this side to develop and grow, playing at Principality Stadium in front of a passionate crowd of more than 65,000.
“It will be a different challenge altogether this week – Wales are renowned for their passing game and their width on attack.”
Eben Etzebeth will captain the Springboks for the 11th time this season, playing in his 67th international match for South Africa.
On the challenge of facing Wales, Coetzee added: “Wales are a good side. They have great attacking ability and a good passing game. They were unfortunate that some of their opportunities this month did not stick.
“They are competitive at set-piece and have a great half-back combination.
“Dan Biggar manages the game well. You can never write them off. From our perspective I am really satisfied with the progress shown this year.
“The players have grown, there is a lot of cohesion, and the evolvement has been satisfactory. If we could finish the tour with three wins, it would show a massive improvement.”
Wales have won their last two games over South Africa in Cardiff, but Coetzee said: “The team is completely different from Cardiff last year, the team environment has changed a hell of a lot and our processes are in place with a clear understanding of how we want to play.
“I made a lot of changes this time last year, but this year there has been continuity and smoother transitions. I am confident these players will take the opportunity this weekend to perform well and end the season on a high.
“The enthusiasm in training this week has been remarkable.”
South Africa XV to face Wales: Andries Coetzee; Dillyn Leyds, Jesse Kriel, Francois Venter; Warrick Gelant; Handre Pollard, Ross Cronje; Steven Kitshoff, Malcolm Marx, Wilco Louw, Eben Etzebeth (capt), Lood de Jager, Siya Kolisi, Pieter-Steph du Toit, Dan du Preez
Replacements: Bongi Mbonambi, Trevor Nyakane, Ruan Dreyer, Oupa Mohoje, Uzair Cassiem, Louis Schreuder, Elton Jantjies, Lukhanyo Am
