He is a regular at the Hooters restaurant at Atlanta, Georgia, and Miss Mariana Villarreal joined the restaurant recently as a waitress.
Both Mr Don Thomas and Miss Villarreal were mere acquaintances.
Mr Thomas had lost both his kidneys to cancer and was desperately looking for a kidney transplant. This happened before Miss Villarreal joined the restaurant.
When she came to know about his grim prognosis, she made a grand gesture by offering one of her kidneys to a man she barely knew, New York Daily News reported.
That offer became a reality and Mr Thomas now has a new lease of life, WXIA-TV reported.
Indeed, both of them went under the knife on Friday. The operation was successful, doctors said, and both are recovering.
They are expected to make a full recovery, 11alive.com reported.
Before going into surgery, she told WXIA-TV: "I said, 'Well I have two kidneys, do you want one of mine'?"
Mr Thomas' reply was: "I will accept it."
So what inspired Miss Villarreal to give him a gift of life?
She recently lost her grandmother to kidney failure, and she was not able to do anything for her grandma then.
Miss Villarreal told WXIA. "If (Don) can live two more years, happy as he's ever been, that's fine with me. That's not up to me. I did my part, now it's God's turn to keep him alive."
Dr Harrison Pollinger, one of the programme directors of the Piedmont Transplant Institute, said both donor and recipient should be able to live healthy lives after the surgery.
He said: "You can live your whole life with just one kidney. You only need one kidney for normal kidney function."
Said Mr Chris Bond of the Georgia Transplant Foundation: "A lot of people don't realise how easy it is - relatively - to give someone a new life."
Said Mr Thomas: "Mariana and I are just two normal people. One who needs help - me - and Mariana, who is so willing to give help."
Miss Villarreal said she hopes their story will inspire others to donate organs to those in need.
This article was first published on May 31, 2015.
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