The 50-year-old suffered a mild heart attack whilst training last week, and he had to be rushed to an unnamed hospital in Johannesburg.
Williams, who currently works as a football pundit, engraved his name in the history of great African footballers when he helped South Africa win their first and only Africa Cup of Nations (Afcon) trophy in 1996, scoring twice against Tunisia in the final.
Wishing ex @BafanaBafana legendary striker Mark Williams speedy recovery. Had a mild heart attack while training this week!!— Dominic Chimhavi (@DChimhavi) August 5, 2017
He is not the first former Bafana Bafana player to suffer a heart attack in recent years.
In the last three years, Mark Fish and Neil Tovey were also admitted with the same problem, but they also recovered successfully.
Goal would like to wish Williams, who also turned out for Mamelodi Sundowns and Jomo Cosmos among other teams during his playing days, a speedy recovery.