It was a chance encounter that changed the lives of two little boys forever.

Isaac Noltin, 12, and 13-year-old Dakotah Zimmer had struck up a friendship at a local swimming pool when other children remarked on how similar they looked.

They had the same hands, the same feet, the same nose, the same haircut - they even walked alike. Then the boys started chatting about their backgrounds – and discovered that they were long-lost brothers!

Dakotah told Isaac that he knew he had a brother he'd never met who was adopted by a woman named Dawn.

"That's my mom's name," Isaac responded.

The boys' amazing and touching story was told by Isaac's adoptive mother, Dawn Noltin to TODAY.com.

She said for weeks before Isaac and Dakotah met, she had been asking her friends and pastor how to tell her son that he had a brother, and knew it had to be before the boys started school because they would be attending the same one in Washington, Missouri, and would surely find out one way or another.

Then the night after Isaac and Dakotah met, Isaac approached his mother and asked if he was adopted.

"He looked at me with his big, black eyes and asked, 'Mom, am I adopted?'" recalled Dawn, 42, a manager at a dry-cleaning company.

"I said, 'What makes you think that?' And he said, 'Because I think I found my brother.'"

"I was so happy that I had a brother. I had always asked for one," Isaac said.

Dawn had met Isaac's mother several years ago when she was heading out to dinner with her ex-husband.

A friend of Dawn's ex-husband invited them to meet his girlfriend and their newborn son. The 16-year-old mother had just given birth to Isaac nine days before, and also had a one-year-old son - Dakotah.

Dawn had been a single mother herself, having her own daughter at 19. She said that her maternal instincts kicked in, and she offered to take care of the newborn.

Months passed, and Dawn received a call that Isaac's biological mother was pregnant again. The woman's grandmother asked if Dawn wished to legally adopt Isaac.

Eighteen months later, and Isaac was legally hers. Isaac and Dakotah's biological mother died in 2007, and their biological father died a year later.

Dakotah and his older sister, Ashley, live with their biological grandmother - Debi Bay.

Debi said that Dakotah always knew he had a brother.

"Though the two didn't know of each other's existence for more than a decade, it seems as though they grew up together, Dawn said.

"You can just tell they're brothers. It's the strongest bond that I've ever seen. It's like they were never separated. For being apart for 10 years and 20 minutes away, they picked up right where they left off."

The boys celebrated their birthdays together recently and now they spend weekends sleeping over, playing Xbox, riding bikes and skateboarding.