Stocks closed firmer for the third straight session, reaching a three-week high, as global equities markets rallied in the run-up to the Christmas weekend break.
By 1500 GMT the rand slipped 0.52 percent to 15.2600 per dollar, sliding back to its weakest in more than a week with the season's typically thin trade volumes exaggerating moves.
The U.S. economy grew 2 percent in the third quarter, slightly slower than the initial estimate, while core inflation beat expectations, setting the stage for further rate increases after that of last week.
The data boosted the greenback, lifting it 0.2 percent against a basket of major currencies while putting the skids on emerging market currencies enjoying a relief rally sparked by falling oil prices.
Oil has more than halved its price in 18 months and sank to an 11-year low of $36.04 a barrel this week.
Government bonds also weakened, with the yields on the benchmark paper due in 2026 adding 2 basis points 9.465 percent.
The benchmark Top-40 index rose 2.15 percent to 45,865.58 points as only two companies on the index closed in the red. The broader All-Share index gained 2.13 percent to 50,839.81 points.
The bourse was buoyed by resources, with Anglo American Platinum, known as Amplats, climbing the sharpest among the blue chips, rising 10.7 percent to 192.20 rand.
Anglo American, which owns the largest stake in Amplats, gained 9.1 percent to 71.95 rand, while BHP Billiton advanced by 6.9 percent to 174.71 rand.
Trade was muted, with 157 million shares changing hands on the stock market, according to preliminary bourse data, well below last year's daily average of 183 million shares.