William speaks of sadness as he leaves Mandela premiere

LONDON- Britain's Prince William called Thursday's death of Nelson Mandela "extremely sad and tragic", immediately after attending the London premiere of a film celebrating the life of the iconic anti-apartheid fighter.

Mandela's daughter Zindzi was also at the screening of "Mandela: Long Walk to Freedom", insisting on her way into the cinema that her father was "fine" but "frail", and that she was "hoping to see more of him."

It is not known where she was when she heard about her father's death, but British news reports suggested she "seemed to be overcome" once inside.

William was told of Mandela's death during the screening, and gave a brief statement following a two-minute silence held at the end of the film.

"We were just reminded of what an extraordinary and inspiring man Nelson Mandela was and my thoughts and prayers are with him and his family right now," he said, flanked by his wife Catherine.

It is believed to be the first time a major royal has given an unscripted response to a large news event.

Members of the audience left the cinema in silence and "shock", according to a report in the Daily Express.

British actor Idris Elba, who plays Mandela on the big screen, said on the red carpet that he hoped the former president would live long enough to see the film.

"I think he [Mandela] has seen parts of the film but ultimately it's about his life, he's been there, he's done it - so he might not even need to see it," he said.