On the 40th anniversary of the fall of Saigon, one of the last infants to be airlifted from Vietnam to Canada is reflecting on his incredible journey, including the shocking discovery that he wasn’t an orphan after all.

Thanh Campbell is one of the thousands of babies that were rescued from Saigon as the Vietnam War came to an end. On April 12, 1975, he was one of 57 babies to be put onto a Canadian Forces Hercules C-130 in a mass evacuation nicknamed "Operation Babylift."

In 2013, he wrote and published a book about his incredible tale called "Orphan 32." The title of his book refers to the number he was given when he boarded the plane on that fateful day.

Campbell spoke to CTV's Canada AM about his journey and future plans on Thursday, which marks the 40th anniversary of the end of the Vietnam War.

In order to be evacuated, all of the babies on the Canadian Forces plane had to be orphans. Campbell, whose birth name was Nguyen Ngoc Minh, had been taken from an orphanage and told he had no family left.

"They wanted to get about 300 to 500 children out at the very end, but they could only prove that 57 of these children were true orphans," he said. "By that time there was no trace of my family."

Campbell eventually arrived in Toronto, where he was later adopted and raised by an Ontario family.

But while growing up in Canada in a white family, Campbell said he always wondered about his Vietnamese roots.

"They are my family, even though I don't look like them – that's my family," he said of his adopted parents and siblings.

His desire to know more about his past eventually led him to reconnect with 42 of the other babies that were put on that plane, during a reunion in 2006.

Remarkably, the story of the reunion made its way to the pages of a Vietnamese newspaper, which was read by Campbell's biological father. And in 2009, Campbell and his biological family were reunited in Vietnam.

Campbell learned that his biological father was part of the South Vietnamese army, and left him in an orphanage to be cared for. He said learning he wasn’t an orphan after all had a deep impact on him.

"It was just remarkable to find out that I had a family, a father who had been looking for me for over 30 years, and never stopped looking for me," he said.

It also brought him comfort knowing that while he was wondering about his biological family as a teen in Canada, they might have been wondering about him and whether or not he had survived.

Campbell said he still keeps in contact with his relatives in Vietnam to this day.

Now, he is planning to tell his story again in a documentary film. He recently launched a crowdfunding campaign to fund the film. 

The proposed documentary will feature more information about Campbell’s biological family, but will also include the stories of the other children who were part of the rescue operation.

"I want to produce this documentary to really share, not only my story, but the story of the children who were part of the plane," he said.

"I want to showcase this part of the story – that the Canadians were involved in airlifting these children out."