Gary, a security guard from Tredegar, Blaenau Gwent, stumbled upon Karen’s post by chance and felt he had to help.
“I saw Karen’s appeal and she mentioned the children, and I thought ‘Karen’s a similar age to my daughter and her youngest child is the same age as my grandson’, and I just thought it’s terrible for the children.
“If It was my daughter, I would be searching everywhere if we had exhausted all avenues through the family and friends, I would want a stranger to come forward. And I thought it would be selfish not to.”
He added: “I thought this lady needs one of my kidneys more than I need two of them.”
Although, Gary, 60, had never met Karen, he immediately volunteered to be tested.
He underwent extensive assessments, including compatibility testing, psychological evaluations, blood tests, cholesterol checks and other medical examinations.
The pair then underwent the six-hour procedure on 15 July at the University Hospital of Wales in Cardiff.
Gary said he never had any second thoughts.
“It’s amazing seeing Karen today, the first time since the transplant and looking so well.
“For me, donating a kidney is simply up there with getting married and having my children, it’s one of the top three things in my life.
“And she’s a very deserving lady and a deserving family.”