Springboks coach Jacques Nienaber has named No.8 Duane Vermeulen as captain in a much-changed team as South Africa employ a split squad tactic having sent several first-team players to New Zealand on Tuesday ahead of their clash with the All Blacks on July 15.
Kleyn, 29, was born in South Africa but moved to Munster in 2016 and became eligible for Ireland via residency. He played five Tests for his adopted country but had not appeared for them since the 2019 World Cup in Japan.
World Rugby introduced a rule change in 2021 that allows Test-capped players to represent a second national team if they are eligible after a period of three years of inactivity with their original country.
Kleyn will partner Marvin Orie in the second row, while packing down in front of them are props Frans Malherbe and Ox Nche, and hooker Bongi Mbonambi. The back row is made up of Vermeulen, Van Staden and Pieter-Steph du Toit.
"Our plan from the outset was to select a squad that we believe has what it takes to beat Australia while at the same time selecting a group of players that could travel to New Zealand to give us the best possible chance to do well in both matches," Nienaber said in a media release from SA Rugby on Tuesday.
"They are a top-class team and have a great tactician in head coach Eddie Jones. This will be the first time we see them play under his leadership in a while, so our focus is mainly on our game and what we would like to do in the match.
"This game is very important to set the tone for us this season, and we know that regardless of what style of play Australia dishes up it's going to a physical and hard match."
SOUTH AFRICA SQUAD
Willie le Roux, Canan Moodie, Lukhanyo Am, Andre Esterhuizen, Kurt-Lee Arendse, Manie Libbok, Cobus Reinach, Duane Vermeulen (capt), Pieter-Steph du Toit, Marco van Staden, Marvin Orie, Jean Kleyn, Frans Malherbe, Bongi Mbonambi, Ox Nche. Replacements: Joseph Dweba, Thomas du Toit, Vincent Koch, RG Snyman, Evan Roos, Deon Fourie, Grant Williams, Damian Willemse.