The concert will raise money for Nelson Mandela's AIDS charity
Celebratory messages have been arriving from around the world for Nelson Mandela, who is celebrating his 90th birthday in London.
Amy Winehouse, Leona Lewis and Queen are among stars performing at a huge concert at Hyde Park in his honour.
The gig comes 20 years after the landmark event at Wembley Stadium, calling for the release of the former South African president from prison.
DAVID BECKHAM, FOOTBALLER
Mr Mandela - happy 90th birthday. Sorry I can't be with you but I'm sure you will have an amazing day. You've got so many people that really respect you as a person and what you've done in your career and in your life. Everybody looks up to you; you are an amazing man. Happy birthday.
VICTORIA BECKHAM, SINGER
Mr Mandela - on behalf of myself, David and our three boys, I want to wish you a very, very happy birthday. Have a wonderful evening.
MORGAN FREEMAN, ACTOR
I'm sending him a "happy birthday" message because he's always been a hero of mine.
GORDON RAMSAY, CHEF
Happy birthday, Mr Mandela - absolutely extraordinary. Congratulations and what a legend!
SHARON OSBOURNE, TV STAR
I'm sending him a birthday message because he changed our world for the better. He's an inspiration.
JOSH GROBAN, SINGER
I want to wish you a very, very happy birthday. I want to thank you from the bottom of my heart for your hospitality welcoming us to your great country and to your offices in Johannesburg. It was one of the greatest honours in my life to meet you and become one of the ambassadors for your foundation. I hope we can meet again soon and I hope you enjoy this very special day.
SUSAN SARANDON, ACTOR
I'd like to wish you a very, very blessed birthday. You've made the world a better place and I thank you. From my children and me, happy birthday.
KATIE MELUA, SINGER
Hello Madiba, I just want to wish you a happy birthday. I hope I look as good as you do when I'm 90. Have a brilliant time and have a great party.
Hey, I just want to wish Nelson Mandela a happy birthday! He's a very inspirational man. He's raised a lot of money for charities.
SHERYL CROW, SINGER
I'd like to congratulate Nelson Mandela on his 90th birthday. Happy birthday.