Argentina lock Manuel Carizza will join Western Province after the Pumas' November tour and will be available for the Stormers' 2014 Super Rugby campaign.
Carizza made his debut for the Pumas in 2004 and has become an ever-present in their second row, playing in 11 Rugby Championship matches in just two years.
The 29-year-old, who has played in 37 Tests, was first discovered playing for the Jockey Club de Rosario, before moving his talents to Biarritz and Racing Metro in the Top 14.
His arrival in Cape Town will bolster the Stormers' locking resources, with the likes of Eben Etzebeth, De Kock Steenkamp and Ruan Botha the current specialist second row options.
Stormers coach Allister Coetzee is delighted that Carizza has opted to join the Cape Town-based franchise.
"Manuel comes with a host of experience in one of the toughest leagues in the world - the Top 14," he told Western Province's official website.
"He's also an automatic pick for Argentina, who boast a powerful pack of forwards, and we're excited to get him into the mix here and part of our systems ahead of the 2014 Super Rugby competition.
"Gerbrandt Grobler will miss a large chunk of 2014 with his leg injury, whilst Manuel's arrival will make up for Andries Bekker's move to Japan.
"Also, a young guy like Ruan Botha had a strong U21 campaign this year and he could only benefit from playing and training alongside an international star like Manuel."