And unmarried Vietnamese pauper Pham Thu Dung, 29, may even demand they give the boy back.

Angelina, 31 picked up the three-year-old boy from an orphanage in Ho Chi Minh city 10 days ago.

But the adoption papers were signed by his grandparents and may not be legal if the mother contests them.

The child's grandad Chien, 55, revealed: "Our daughter is a heroin addict and she is a bag of trouble. Her life has been ruled by drugs since she was 16.

"When she finds out that a rich movie star has adopted her baby, she WILL go after Angelina Jolie for money and make trouble for her. She may even try to take the child back."

And granny Nhan, 51, added: "We are delighted he has gone to such a wonderful home. But my daughter is very smart - and she is also very stubborn, wayward and difficult."

Speaking at their rundown home in a poor suburb of Ho Chi Minh City, Chien, told how his daughter became pregnant after an affair with a married man at the garment factory where she worked.

Emaciated and desperate for a fix, Dung gave birth to a seriously underweight son on November 29, 2003. Doctors feared the child would be born a heroin addict.

Two days afterwards, as he fought for life in a special care baby unit, she sneaked out of the hospital leaving her child behind because she couldn't afford the £15 medical bill - the equivalent of a month's wages.