A woman who wanted to give a homeless man a little spare change accidentally gave him her engagement ring by mistake.

A WOMAN in Kansas is thanking her lucky stars after a homeless man returned her diamond engagement ring which she accidentally dropped into his coin cup days earlier.

Sarah Darling was walking past The Plaza in Kansas City last Friday when she spotted homeless man Billy Ray Harris and opened her purse and emptied all of her change into his coin cup.

What she didn't realise, was that she had also dropped her large diamond engagement ring into the cup as she had put it in her purse with her coins.

"My rings were bothering me, so I put them in my coin purse," she told local TV station KCTV.

Mr Harris didn't notice the bit of bling until about an hour later.

"The ring was so big that I knew if it was real, it was expensive," he said. What he did next, surprised many as he kept the ring and waited for the owner to show up again so he could return it.

Ms Darling meanwhile, was distraught when she discovered that her ring was missing.

"I was so incredibly upset because, more than just the value of the ring, it had sentimental value," she said.

When Ms Darling returned to The Plaza and found Mr Harris she got the shock of her life.

"She squatted down like you did like right there and says ‘Do you remember me?' And I was like, "I don't know. I see a lot of faces." She says, "I might have gave you something very valuable." I said, "Was it a ring?" And she says, "Yeah." And I said "Well, I have it,'" Harris said.

Harris said he kept the ring for the rightful owner because it simply wasn't his.

"My grandfather was a reverend. He raised me from the time I was six months old and thank the good Lord, it's a blessing, but I do still have some character," he said.

Ms Darling was so grateful to get her sparkling engagement ring back that she gave Mr Harris all the money she had in her wallet as a reward.

She said getting the ring back was "a miracle" and it goes to show that you shouldn't be quick to judge the less fortunate.

"I think in our world we often jump to like the worst conclusion, and it just makes you realize that there are good people out there," she said.