Nick Fenton-Wells, the Western Province and Stormers flank, has agreed to join Saracens in July.
Mark McCall, Director of Rugby, said: “We have been following Nick’s progress for some time.
"He has the heart of a lion, and we are delighted he has decided to join us.”
Fenton-Wells said: “Everybody in SA rugby follows what is happening at Saracens, and I’m looking forward to joining a club that continues to break new ground in so many ways.
"I'm really excited to be joining such a special club and I’m very grateful for this opportunity.”