The 24-year-old walked out on his chance of playing for his own country claiming his international chances were limited by a racial quota season in South Africa.
Pietersen, who plays for English county Hampshire, featured in all four of Englands One-dayers against Zimbabwe before Christmas, will fly out to South Africa with the rest of England's specialist One-day players on Monday.
Chairman of Selectors, David Graveney, said: "We feel that it is prudent to add Kevin to the squad as the team face seven One-day Internationals in 15 days following hard on the heals of an intensive Test Series.
"Kevin had an encouraging start to his international career in Zimbabwe and we feel that his inclusion will give the captain and coach another option if they decide a different balance to the side is required."
Pietersen, who hit a maiden half-century for England in Zimbabwe, has had to spend four years gaining eligibility for his adopted country.
His controversial decision sparked an angry rebuke from South African skipper Graeme Smith who accused him of walking out on his country.
"He ran out when things got tough," Smith told a magazine. "If he didn't want to be here then we don't want him here."