A stranger in the Christmas spirit picked up an Iowa family’s $211 grocery bill at Walmart last week, causing the family’s matriarch to cry tears of joy at the register for the "angel of Christmas."

The Modlins recounted the experience to Des Moines news station KCCI on Wednesday, of having a stranger pick up the tab on the $211 bill.

The family’s matriach, Ruby Modlin, said she and her family were grocering shopping at the Walmart in Altoona, Iowa, when she spotted the man who would later foot the family’s $211 bill.

"I kept noticing this man, and I'd smile at him," Modlin said, telling KCCI that at first she thought maybe they graduated from the same high school.

When it came time to pay, the man stepped in front of Modlin and her family and swiped his credit card.

"I said, ‘What?’ He said, ‘I’m paying for this.’ I said, ‘No, you’re not.’ He said, 'Yes, I am,’” Modlin told KCCI.

The man then handed the Iowa family the receipt for the grocery bill and exclaimed, “Merry Christmas!”

The stranger then explained why he decided to be generous around Christmas.

“He said, ‘That’s my daughter and wife over there. We just wanted to come out and do something nice for somebody, and we picked you guys,’” Modlin said.

The man and his family then walked away without giving his name, so the Modlins still don’t know who is responsible for the goodwill.

"I was still standing there in shock. We were too busy crying, and the register people were smiling," Modlin told the news station.

Modlin’s husband, Ray Modlin, dubbed the family “angels of Christmas.

“They're just sent from heaven. There's no amount of words that can thank people like that,” he said.

Ruby Modlin said the kindness came at an opportune time because she has been in and out of hospitals with liver failure for half of 2012.

Modlin said she was touched by the stranger and added that she has been on a waiting list for a liver transplant for 18 months.

Modlin had a message for the stranger and his family.

"I just want to thank them. I don't know who they are, but I hope they see this. And from my husband, and granddaughter and me, we just want to thank them," she said.