Nelson Mandela's condition is said to have "improved" overnight acording to the South African President, Jakob Zuma.
"He is much better today than he was when I saw him last night," commented Mr Zuma on Thursday after seeing the former leader in hospital.
Ndileka Mandela, the former South African President's granddaughter, said Mr Mandela is now in a "critical but stable" condition on life support.
"We thank everybody for giving support and praying with us," said Ndileka. "There's been a lot of comfort in the messages of support, people that send us personal messages.
"They've given us strength to carry on," she continued, referring to the flowers and gifts being left outside the hospital, "and give him positive energy."
Mr Mandela's family have remained close by since the former leader was admitted to hospital with a lung infection two weeks ago.
His wife Graca Machel has been keeping a constant vigil by his bedside. She was joined by other members of his family, including his former wife Winnie, daughter Makaziwe and granddaughter Ndileka.
South African President Jacob Zuma has also visited, and confirmed that Mr Mandela's health has deteriorated.
Celebrities around the world, from David Beckham to Hillary Clinton, are praying for Nelson Mandela, 94, as the anti-apartheid icon remains critically ill in hospital.
David has been at the forefront of a campaign to cement the former President of South Africa's legacy, and now could be a fitting time to fully promote it.
"This is an important time to bring Nelson Mandela's official legacy to life," he said in a post on Facebook, sharing a Nelson Mandela Day pledge.
"Show your support now. Join millions of us growing his legacy for good at http://bit.ly/P5OZuk #MandelaDayPledgePlease share your pledge to make this a better world – we can make it happen..."
David will most likely be taking part in this pledge, which sees each participant giving 67 minutes of their time on 18 July, the former President's birthday, in recognition of his 67 years of public service.
The footballer, who has called Nelson a "father figure for South Africa" in the past, met the inspirational leader in 2003 when he was England captain.
"It's great to be here today," said David, seated next to him at a friendly match against South Africa and presenting him with an England football shirt. "It's an amazing honour for all of us."
Other celebrities have flooded Twitter to share their support for the critically-ill leader.
"Bill, Chelsea & I have sent our love and prayers to our great friend, Madiba, his family and his nation during this difficult time," tweeted Hillary Clinton.
Madiba refers to Nelson's clan name, and has been used by other celebrities on the social media site.
"My thoughts and prayers are with our father Madiba, one of the greatest men in the world. God Bless you Madiba," posted Formula 1 racer Lewis Hamilton.
Rihanna also showed her support, tweeting, "Nelson Mandela....one of the most incredible men to ever walk this earth!!! Sending prayers up to the Heavens for you! #AngelOnEarth".