After more than 60 years as friends, two men were shocked to learn that they are brothers.
Alan Robinson and Walter Macfarlane made the discovery after taking a DNA test through the popular genealogy website Ancestry.com, KHON reported, according to the Daily Mail.
Robinson and Walter first met in the sixth grade while growing up in Oahu, Hawaii, notes the Daily Mail. They were both born and raised on the island and even played football together in high school.
"He was the partier, I never went to or did any partying in high school," said Walter, who never knew his father.
Robinson, who was adopted, explained: "I had a younger brother that I lost when he was 19, so I never had nieces or nephews. I thought I'll never know my birth mother, I'll never have any nieces or nephews."
Walter had spent several years searching online for answers, without success. Finally, he turned to family DNA matching websites.
"So then we started digging into all the matches he started getting," explained Walter's daughter, Cindy Macfarlane-Flores.
The strongest match was a person with the username Robi737, who had several DNA markers in common with Walter, including identical X chromosomes.
"As a nickname everybody called him Robi and he flew 737s for Aloha Airlines, he was a pilot," Cindy said of Robinson.
Walter was unaware that Robinson was also using Ancestry.com to search for his roots, and it's not clear whether or not Walter initially suspected that Robi737 was his old friend.
But ultimately it became apparent to both of them, and they concluded that they have the same birth mother, and were born 15 months apart.
"It was a shock," said Walter of the realization.
"Yeah it was shock, definitely, and then we thought about it and compared forearms," Robinson said. Walter sarcastically added: "Yeah hairy arms, that did it!"
On Dec. 23, the two men shared the news with their friends and family.
"It was an overwhelming experience, it's still overwhelming. I don't know how long it's going to take for me to get over this feeling," Robinson said. "This is the best Christmas present I could ever imagine having."
"It really is a Christmas miracle and we're just so happy that we found it," Walter's daughter added.
Ancestry.com was started in 1996, and launched its DNA database in 2012 to exploit the latest advances in DNA analysis, notes HuffPost.
As for Walter and Robinson, they are reportedly making plans to travel and enjoy retirement together.