England cricketer Ben Stokes's father Ged has been taken to a Johannesburg hospital in a "critical condition".
The all-rounder – and current BBC Sports Personality of the Year – and his family are at his bedside.
The England and Wales Cricket Board (ECB) said in a statement the former rugby league player was admitted with a "serious illness" on Monday.
Ben Stokes will miss training with his team-mates on Christmas Eve ahead of England's First Test against South Africa which starts on Boxing Day.
It is not yet known whether the hero of England's World Cup and Ashes summer will be able to play in the match.
The ECB said: "Ben Stokes's father, Ged, was admitted to hospital on Monday in Johannesburg after suffering a serious illness. He remains in a critical condition.
"The England and Wales Cricket Board, with the support of Ben and his family, request that the media and public respect Ben and his family's privacy at this time."