The Queen and the Prince of Wales are among those who have paid tribute to South Africa's first black president Nelson Mandela who has died at the age of 95.
The world learnt of his death as royalty, celebrities and fans were watching the royal premiere of a film chronicling his incredible life.
In a twist of fate, it was during the screening in London's Leicester Square that Mr Mandela's daughter Zindzi Mandela was informed her 95-year-old father had died peacefully at home.
The Queen said she is ''deeply saddened'' to learn of Mr Mandela's death, saying he ''worked tirelessly for the good of his country''.
The anti-apartheid icon, held in the highest esteem across the world for leading his nation's transition from white-minority rule in the 1990s after 27 years in prison, had been receiving medical care for a lung infection at his home.
Mr Mandela spent his final months surrounded by family after being released from hospital following a three month stay and passed away peacefully, President Jacob Zuma announced in a televised address last night.
A statement from Buckingham Palace said: ''The Queen was deeply saddened to learn of the death of Nelson Mandela last night. He worked tirelessly for the good of his country, and his legacy is the peaceful South Africa we see today.
''Her Majesty remembers with great warmth her meetings with Mr Mandela and sends her sincere condolences to his family and the people of South Africa at this very sad time.''
Prince Charles said Mr Mandela was "the embodiment of courage and reconciliation".
He added: "He was also a man of great humour and had a real zest for life.
''With his passing, there will be an immense void not only in his family's lives, but also in those of all South Africans and the many others whose lives have been changed through his fight for peace, justice and freedom.
''The world has lost an inspired leader and a great man. My family and I are profoundly saddened and our thoughts and prayers are with his family.''
Screams rang out in the auditorium at the film premiere as the news was broken to Ms Mandela, although fellow audience members were not informed of the death until after the film.
Speaking before the screening of Mandela: Long Walk To Freedom, she said her father was doing well, when asked about his health.
She said: "My father is fine. He's 95 years old and he is pretty frail. We are hoping to see more of him."
The Duke of Cambridge, with Kate beside him, gave a sombre tribute after leaving the cinema.
"It was extremely sad and tragic news," he said.
"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."
Damian McCarthy, 45, who was at the screening, said: "I've never felt an atmosphere like that. It was unbelievable. It went from being quite a high-spirited occasion to absolute silence - stunned silence.
"It's one of those moments where people say, 'Do you remember where you were?' It's definitely put a bit of a bizarre twist on the premiere."
After the film, Idris Elba, who plays Mr Mandela, took to the stage with producer Harvey Weinstein to hold a moment's silence to honour the great man.
''Our nation has lost its greatest son,'' Mr Zuma said. ''Our people have lost a father.
''What made Nelson Mandela great was precisely what made him human. We saw in him what we seek in ourselves.''
A law student turned freedom fighter, his battle to end the system of apartheid that tore apart his nation led to his incarceration in a tiny cell in the infamous Robben Island jail.
Prime Minister David Cameron said ''a great light has gone out in the world'' while US president Barack Obama mourned the loss of ''one of the most influential, courageous, and profoundly good human beings that any of us will share time with on this earth''.
Mr Mandela was awarded the Nobel Peace Prize in 1993 and was elected South Africa's first black president the following year.
American civil rights leader Jesse Jackson said Mr Mandela's ''imprint'' would be ''everlasting''.
Mr Zuma said the man known as Madiba would be afforded a state funeral and South African flags would be lowered to half-mast until the funeral.
''Our thoughts are with the South African people who today mourn the loss of the one person who more than any other came to embody their sense of a common nation,'' he said from Pretoria.
''Our thoughts are with the millions of people across the world who embraced Madiba as their own and who saw his cause as their cause.''
The clearly emotional leader added: ''As we gather to pay our last respects, let us conduct ourselves with the dignity and respect that Madiba personified.
''Let us be mindful of his wishes and the wishes of his family as we gather wherever we are in the country and wherever we are in the world.
''Let us recall the values for which Madiba fought.
''Let us reaffirm his vision of a society in which none is exploited, oppressed or dispossessed by another.''
Flowers and a framed picture of Mr Mandela were laid at the base of his statue in Parliament Square in the early hours.
One tribute on a card read: ''Thank you for the sacrifices you made for all of us.''
A second read: ''May God shine light on your homecoming in heaven.
''Rest in Peace Mr Mandela.''
Two heritage wardens stood near the statue as passers-by stopped to pay their respects.
The flag at No 10 will be flown at half-mast in honour of the former leader, who was a ''hero of our time'', Mr Cameron announced.
Former prime minister Sir John Major said Mr Mandela "left an indelible mark on his time that few have ever equalled".
Hillary Clinton, former US secretary of state, said Mr Mandela was "a champion for justice and human dignity, with unmatched grace".
Mr Mandela's body will lie in state for three days in Pretoria, the BBC said, before a funeral is held on Saturday in Qunu, the village in Eastern Cape where he was born.
Sir Shridath Ramphal, Commonwealth secretary-general from 1975 to 1990, said in a statement: ''Tomorrow's children will not be able to say, as we can with pride and a deep sense of privilege, that we lived in the time of Nelson Mandela, a unique and memorable human being."
David Miliband, president and CEO of the International Rescue Committee, said Mr Mandela's life shows how ''personal character, values and personality at the top can make and break nations''.
He also said Mr Mandela was "an example for politicians but also for people".
Deputy Prime Minister Nick Clegg said: ''Every so often history produces an individual whose message is universal, and Nelson Mandela will be mourned and missed on every continent around the globe."
Labour leader Ed Miliband called his work to unite South Africa in the face of personal hardship and oppression ''extraordinary''.
He said: ''The world has lost the inspirational figure of our age. Nelson Mandela taught people across the globe the true meaning of courage, strength, hope and reconciliation."
Foreign Secretary William Hague said Mr Mandela's life story is "a compelling and inspiringly profound political journey".
Former prime minister Tony Blair said the political leader was a ''great man'' who had made racism ''not just immoral but stupid'', while former prime minister Gordon Brown called Mr Mandela ''the greatest leader of our generation''.
In a statement released through NBC News, former US president George Bush said: ''President Mandela was one of the great forces for freedom and equality of our time. He bore his burdens with dignity and grace, and our world is better off because of his example."
Westminster Abbey will hold a national service of thanksgiving for the life of Mr Mandela after the state funeral in South Africa.
A book of condolence will be opened at St Margaret's Church at the Abbey from 9.30am today.
The Dean and Chapter of Westminster sent a message of condolence to the High Commissioner for South Africa.
The message read: "The Dean and Chapter of Westminster sends condolences to the family of Madiba and to the government and people of South Africa on the death of their former President, Nelson Mandela.
"He was an iconic figure who changed irrevocably the course of history in his country and the African continent and who changed the world's attitude to issues of equality and human justice."