Krige, 29, made his debut for the Springboks in 1999 against Italy. He led the side 18 times and has a total of 39 caps. He has already worked with Saints head coach Alan Solomons at international, Super 12 and provincial level. Solomons said: 'Corne is a fantastic bloke with strong leadership qualities as evidenced by his captaincy of Western Province, the Stormers and the Springboks.
'He is a hard-nosed, abrasive openside flanker in the mould of Budge Pountney. I count him among the top opensides in world rugby.' Krige will begin his role with the club ahead of Saints' pre-season friendly against Edinburgh Rugby at Franklin's Gardens.
Former Saints prop Garry Pagel, who knows Krige from his South African playing days, added: 'Corne will be without question one of the most influential signings made by the Saints in the last few years.
'I always found that he was a dedicated, loyal and hard-working player, on and off the field, and that he played for his teammates and was prepared to put in the hard work.'
The Saints, Heineken Cup winners in 2000, will play Glasgow, Llanelli Scarlets, and last year's beaten finalists Toulouse in Pool 3 in this season's competition.