"Graeme was a wonderful cricketer for South Africa and a wonderful captain," said current captain Hashim Amla. Smith will be with the team for the rest of the four-match series.
South Africa will make at least two changes following a crushing 241-run defeat in the first Test in Durban.
Amla announced that Kagiso Rabada will replace the injured Dale Steyn. He also dropped a strong hint that Quinton de Kock would come in as a wicketkeeper and batsman, with AB de Villiers relinquishing the gloves and playing as a specialist batsman.
"If Quinny does come in he will take a load off AB and he has also been in very good form with the bat. If he does play, the selectors will have to decide who they will leave out. It will be a tough decision, whether it is Faf (Du Plessis) or JP (Duminy) because these have been integral guys in our team for many years."
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Fast bowler Kyle Abbott will undergo a fitness test ahead of the match after feeling tightness in his left hamstring at the end of the first Test. If Abbott does not play, he will be replaced by either Chris Morris or Hardus Viljoen, who are both uncapped.
South Africa have not won a Test since last year's New
Year fixture against the West Indies at the same venue.
"When you win or lose a cricket game you are either going to be praised or there is criticism," said Amla. "That's just the nature of international sport. When people criticise the team there's going to be some value in it. You take it on the chin and move on. Wherever there is value that can be added you've got to take it."
"Graeme can give guidance to the batters, which he already has today," said Amla. "It is a confidence type of thing. You've got to almost refresh what the processes are that made you successful.
"Graeme knows more than most how tough it is to play cricket and how it is to go through tough times. Early in his career there were a few crushing defeats and he is well aware of how difficult it is and how important it is for a team to reassess and get back. He's got good know-how about Test cricket and we've got a lot of youngsters who can draw on that.