BBC newsreader George Alagiah is set to undergo treatment for bowel cancer and will be off air "for a while", the corporation has said.
Alagiah, 58, who presents BBC News at Six as well as GMT on BBC World News, will take a break from presenting while he undergoes his treatment.
The BBC said Alagiah was "grateful" to wellwishers and was optimistic of a positive outcome.
A BBC spokesperson said: "George asks that he and his family are given the space and privacy they require whilst he recovers. Our thoughts are with him and his family and we send them our very best wishes during this time."
His presenting role would be taken over by "familiar faces from BBC News" until further notice.
Alagiah joined the BBC in 1989 and spent years as its leading foreign news correspondent before making the move to presenting in 2003.
He has reported on the Rwandan genocide and the war in Kosovo.
He was awarded an OBE in the 2008 New Year's Honours list.
About 41,000 people are diagnosed with bowel cancer every year in the UK.