The results "absolutely surprised" the both of them, according to Niamh Geaney, who added that she and her doppelganger Irene Adams "couldn't believe" the results.
Geaney -- who's from Dublin, Ireland -- told ABC News today she first connected with Adams -- who's from Sligo, Ireland -- this past November after a friend of Adams' told her she looked like "that doppelganger girl on the news."
Coincidentally, a friend of Adams' brother also contacted Geaney around the same time.
"We got in touch, met up and it was absolutely surreal to see yet another one of my doppelgangers in the flesh," said Geaney, 27. She explained that Adams, 28, is actually the third doppelganger she's discovered so far since creating Twin Strangers, a website and tool that uses facial recognition software to match you to a potential lookalike.
"We clicked instantly, and just like my second doppelganger, she not only looked exactly like but also acted like me," Geaney said. "It was like watching myself. Our facial expressions are exactly the same, our eyes and nose crinkle the same way, we smile the same and she also talks with her hands just like me."
Dozens of users commented on video of Geaney's and Adam's meetup, suggesting the two should get a DNA test since the both of them were from Ireland and could actually be "10th cousins or related somewhere down the line," Geaney said.
This past December, the two went to national DNA testing center DNA Ireland, where they gave samples of their saliva.
The samples were used for three tests that determined the probability of the two being sisters, half sisters, or related at all based on lineage traced up to 20,000 years ago.
Below are the results, which were delivered earlier this month to Geaney and Adams:
Probability of Being Full Siblingship
There was only a 0.0006 percent chance the two had the same parents.
Probability of Being Half Siblingship
There was only a 0.1 percent chance the two shared one parent.
Probability of Sharing a Common Ancestor Up to 20,0000 Years Ago
Rather than a percentage, this test gives users their haplogroup, which is a letter assigned to a genetic population group of people who share a common ancestor on a patrilineal or matrilineal line.
Geaney had Haplogroup H, and Adams had Haplogroup T.
"We were shocked," Geaney said. "We thought, 'OK, we definitely have to have relatives from the same place somewhere down the line,' but that wasn't the case."
Geaney added that she believes the test has "fascinating implications" and that the test could suggest "doppelgangers really are, in fact, a mysterious phenomenon."