Kleyn, 29, was born in Johannesburg but joined Munster in 2016 and qualified for Ireland through residency. He played five Tests, including two at the 2019 Rugby World Cup in Japan, which were also his last.
His form for Munster this season has caught the eye as he played a key role in beating his former side the Stormers in the final of the United Rugby Championship last month.
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.
The competition among the locks in the Springbok squad is fierce, with Lood de Jager, Eben Etzebeth, Marvin Orie and RG Snyman named in the training squad on Saturday, while loose-forwards Pieter-Steph du Toit and Franco Mostert are also accomplished in the second row.
The training camp will be staged in Pretoria from next week, with the team’s Rugby Championship opener against the Wallabies at Loftus Versfeld on July 8.
Defending champions South Africa have been drawn in the same pool as Ireland, Scotland, Tonga and Romania at the World Cup in France, with two teams qualifying for the quarter-finals.
SOUTH AFRICA SQUAD:
Thomas du Toit, Steven Kitshoff, Vincent Koch, Frans Malherbe, Ox Nche, Trevor Nyakane, Joseph Dweba, Malcolm Marx, Bongi Mbonambi, Lood de Jager, Eben Etzebeth, Marvin Orie, RG Snyman, Jean Kleyn (subject to World Rugby approval), Pieter-Steph du Toit, Siya Kolisi, Evan Roos, Kwagga Smith, Marco van Staden, Duane Vermeulen, Jasper Wiese, Jean-Luc du Preez, Deon Fourie, Franco Mostert, Faf de Klerk, Jaden Hendrikse, Herschel Jantjies, Cobus Reinach, Grant Williams, Manie Libbok, Handre Pollard, Damian Willemse, Lukhanyo Am, Damian de Allende, Andre Esterhuizen, Jesse Kriel, Kurt-Lee Arendse, Cheslin Kolbe, Willie le Roux, Makazole Mapimpi, Canan Moodie.