BBC NI sports presenter Stephen Watson has said he will never be able to thank enough the anonymous person who donated a kidney to him.
He said he felt "completely different" from the day after he received a kidney transplant three weeks ago.
"Six, eight weeks ago I was having dialysis four times a week, five hours at a time - I don't have to have that any more," he said.
"Once I get over the tiredness, I'll be back operating at full pace again."
It was the second kidney transplant Stephen has had - he received the first from his father 30 years ago.
He said the surgeons at Belfast City Hospital are world leaders in transplantation.
"They do more live transplants than anywhere else in the world," he said.
"From doing 30 transplants a year, this year I think they'll probably do upwards of 120 transplants, which is more than two a week.
"There are people walking in off the street saying: 'I want to donate a kidney to a stranger.'
"I believe it's the greatest gift you could ever offer or give."
Stephen said the living kidney donor had given him the gift of life.
He said he was "up walking around" the day after his transplant.
"It's amazing just how quickly how good you can feel after a transplant - it's unbelievable," he said.
Stephen said he plans to take January off to rest and return to work in February.
He said he wanted to "thank everyone for the unbelievable messages of support".
"I have been completely and utterly overwhelmed," he added.
Stephen was back at work for one day on Friday presenting motorcyclist Jonathan Rea with the BBC NI Sports Personality of the Year award.
He said he hoped his story would help persuade people to take part in the live kidney donation scheme and that other people awaiting transplants should stay positive.
"I was a very low percentage for a match of a transplant, but I kept the faith, I stayed positive and I got my transplant," he said.