A pair of unlikely best friends celebrated Halloween together Monday.

Four-year-old Norah Wood befriended 82-year-old Dan Petersen in an Augusta, Georgia, supermarket on her birthday in September. The story quickly went viral.

Mom Tara Wood said Norah spotted Dan, who looked a little gruff and grumpy, and called out to him.

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“She said, ‘Hi old person! It’s my birthday today!’” Wood told Hot Topics. “But then, his expression softened. He asked, ‘How old are you today?’”

Since that day, Norah and “Mr. Dan” have become close friends.

“Every single day she asks about him,” Wood said.

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Wood drives Norah to his home several time each week to visit him.

Wood said Norah worries about Dan being lonely, so she gave him a special gift to keep him company.

“She said ‘Mr. Dan doesn’t have a dog in his house. I think he’s sad,'” Wood recalled. “So we went to a store and found a stuffed puppy and asked to buy it for him.”

A friend of Dan’s reached out to Wood as her story started to go viral. The woman told her that Dan’s wife recently died, and he hadn’t smiled since. But little Norah completely changed that, and he’s happier than he’s been in a long time.

“Something in her recognized something he needed,” Wood said. “It’s magical.”

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On Monday, Norah visited Dan for Halloween dressed in her Minnie Mouse costume. Photos show Norah and Dan sharing candy and exchanging hugs.

Wood says she’s touched that her daughter has befriended someone who needed love.

“I feel lucky to be the one to watch it happen,” Wood said. “It’s magical.”

>> Click here to see the photos