Jacques Kallis, very much the cornerstone of South Africa's Test side, is embroiled in a controversy over his refusal to sing the national anthem. A report in South Africa's Sunday Times suggests that Cricket South Africa will ask for an explanation from him after the Johannesburg Test.

The current anthem, first sung in 1996, is a combination of Nkosi Sikelel'iAfrika, which was a symbol of the resistance to Apartheid, and Die Stem (The Call of South Africa), which was adopted as the national anthem by the Apartheid regime in 1957. The issue regarding Kallis was first raised by a Sunday Times reader, Ebrahim Sadak, who wrote in to Cricket South Africa asking whether Kallis thought he was indispensible or "anti new SA".

Ros Goldin, Cricket South Africa's marketing manager, wrote back to him saying: "While we do encourage all our players to sing the anthem, it is at their discretion whether they wish to do so. Jacques's choice not to sing is certainly not due to his being anti SA or because he thinks he is indispensable! It is simply his right within a democratic environment not to sing."

She went on to cite examples of other sportsman who didn't sing, including some South Africa footballers and rugby players, but Sadak wasn't appeased. Eventually, he got a reply from Kallis himself. "It is my choice whether I sing or do not sing the anthem," it said. "I certainly do not have to explain my reasons to anyone, especially you. I do have good and valid personal reasons and I intend to keep it that way."

When the newspaper contacted Cricket South Africa, Gerald Majola's response was slightly different from Goldin's. Majola, the chief executive, said that the organisation "insists on having the SA anthem sung".

We haven't heard the last of this issue, especially given the hyper-sensitivity when it comes to matters of national identity. Three years ago, Springbok rugby was plunged into chaos after Geo Cronje, an Afrikaner with a beard straight out of the Voortrekker era, allegedly refused to share a room with a coloured team-mate, Quentin Davids. For all you know, Kallis might just be shy about singing in public, like so many of us, or maybe there's more to his silence than meets the eye.

Dileep Premachandran is an associate editor at ESPNcricinfo