Football star George Best managed to get out of his bed and speak to family and friends as his surgeon said his condition was "greatly improved".
George Best received a liver transplant in 2002
Professor Roger Williams said Best was "out of bed and sitting up talking" but would remain in intensive care for at least several days.
Best's manager Phil Hughes added that the star was in "incredible pain".
The 59-year-old is trying to recover from life-threatening infections that spread to his kidneys and other organs.
Best recently opened his eyes and started to breathe without the help of a ventilator at London's Cromwell Hospital. He later said a few words to sister Julie and his girlfriend Ros Hollidge.
Professor Roger Williams, who oversaw his liver transplant three years ago, earlier said he was pleased with his progress and remained hopeful.
"[It's] a big move forward from yesterday, and yesterday was better than the day before, so all in all its going very well," he said.
"The kidneys are working reasonably well. To sit him out of bed after the last few days... is a measure of just how much he has improved.
"If he goes on like this, without any setbacks or new complications, we really are very hopeful."
Mr Hughes described the improvement as "great news".
"He isn't yet able to hold conversations, but he did manage to say a few little things this morning," he said.
Best's illness is thought to be related to immuno-suppressant drugs he must take to stop his new liver, which he received in July 2002, being rejected.
GEORGE BEST'S HEALTH
March 2000: Severe liver damage diagnosed
February 2001: Treated for pneumonia
April 2001: Anti-alcohol pellets implanted into his stomach
July 2002: Undergoes liver transplant
November 2004: Routine operation to check on liver transplant
October 2005: Treated for kidney infection in intensive care
His condition deteriorated severely last week after four weeks of hospital treatment for an infection, but had improved by Saturday.
Current and former football figures have voiced their support and concern for the ex-footballer, including Manchester United manager Sir Alex Ferguson and Best's former colleague Denis Law.
Best was arguably the most naturally gifted British footballer of his generation.
He made his professional debut for Manchester United in 1963, aged 17, and helped the club become the first English side to lift the European Cup, in 1968.
He was voted both English and European Footballer of the Year that season and also won 37 caps for Northern Ireland.