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A Cambodian aid worker is making extraordinary claims about Angelina Jolie's 2003 adoption of eldest son Maddox Jolie-Pitt.

Mounh Sarath, 51, tells Britain's The Sun on Sunday that he signed official papers in Cambodia claiming he was Maddox's father in order to help speed along the boy's adoption all those years ago.

He also claims he still has legal power of attorney over the now-teenager and showed The Sun on Sunday the adoption document filed with a court in Cambodia's Battambong province in August 2003 to back up his claims.

He explained the lie, telling the paper, "She had to change his name, so the only way was for me to do it. I said he's my son."

"In court documents, Maddox is still my son," he said. "She never cleared this up."

Despite his claims, there is no evidence that either Angelina, 41, or then-husband Billy Bob Thornton, 61 -- who was also involved in Maddox's adoption before he and Angelina divorced -- knew what Mounh did.

According to MailOnline, Angelina has previously said she went to "great lengths to ensure Maddox did not have a living birth mother in Cambodia" and that she would "never rob a mother of her child."

Maddox's adoption took place at a time when the United States was imposing tougher restrictions on adopting kids from Cambodia because of trafficking concerns.

Lauryn Galindo -- the adoption agent who handled Angelina and Maddox's case -- spent time in prison after reportedly falsifying the names, birth dates and birth places of Cambodian children who were adopted by Americans. (She denied this at the time, telling ABC's "20/20," "I have never been involved or charged with anything other than paperwork errors. And that's what I pled to, that's what I'm going to go to prison for."

While making his serious claims, Mounh -- who met Angelina through charity work -- also revealed he and the star have since fallen out. "I would be happy if Cambodia didn't see her again," he said.

Angelina was in Cambodia in February to promote "First They Killed My Father," a movie she directed for Netflix about the Khmer Rouge and Cambodian genocide. Maddox worked on the film.

Neither Angelina nor soon-to-be ex-husband Brad Pitt, who legally adopted Maddox after settling down with Angelina, have commented on the claims.

In addition to Maddox, the former couple are also parents to son Pax, 13, who was adopted from Vietman; daughter Zahara, 12, who was adopted from Ethiopia; and biological children Shiloh, 10, who was born in Namibia, plus 8-year-old twins Knox and Vivienne, who were born in France.