Mounh Sarath, a Cambodian aid worker, told the British publication that he is in fact Maddox's biological father.
The 51-year-old believes he "officially has power of attorney over the boy," and raised the issue after he claimed he'd "fallen out with the Hollywood actress."
“I would be happy if Cambodia didn’t see her again,” he said to the newspaper, after showing them the adoption document filed with a court in Battambong province in August 2003.
“In court documents, Maddox is still my son. She never cleared this up.”
Adding, "She had to change his name, so the only way was for me to do it. I said he's my son."
There is no evidence that suggests that Angelina would be aware of these allegations.
The actress adopted eldest child from a Battambang orphanage in March 2002, through agent Lauryn Galindo, who has since been jailed in America.
Lauryn was charged and sentenced to 18 months after it was discovered that she falsified names, birth dates and places of birth of Cambodian children in order for them to be placed with American families.
Angelina denied she was involved in activity, saying at the time that she went to “great lengths to ensure Maddox did not have a living birth-mother in Cambodia."
“I would never rob a mother of her child. I can only imagine how dreadful that would feel.”
She's also said in the past, “Personally, I prefer to stay on the right side of the law. I would never take a child away from a place where adoption is illegal.”
The Hollywood starlet first fell in love with Cambodia while filming Tomb Raider in 2000.
The 41-year-old chatted to People during the press junket for her film First They Killed My Father.
Speaking of the country, of which she is a citizen of, she mused, "We’ve been coming back and forth for 17 years, it feels like a second home to me."
"The children have close ties to the children here, many of them are their best friends. Maddox is happy to be back in his country."