Jolie pictured during her last visit to Cambodia in July 2004

King Norodom Sihamoni signed a royal decree approving the citizenship on 31 July, officials said on Friday.

Jolie, who adopted a Cambodian boy in 2002, was offered citizenship during her last visit to Cambodia in 2004.

The Tomb Raider star, who has since adopted a second child, said at the time she would be "thrilled" to accept.

"This is what we have dreamed for her for a long time," said Mounh Sarath, director of the Cambodian Vision in Development group.

'Good heart'

Jolie, 30, has pledged $5m (£3.2m) to set up a wildlife sanctuary in the north-western province of Battambang, where she has bought a home.

But Mr Sarath said the actress deserved citizenship "not because of the money she has given but [for] her good heart and love" for the Cambodian people.

Toun Siphan, director of the government's international relations department, said her adoption of a Cambodian orphan - Maddox, now four - had also played a part in the decision.

The legal document signed by the king gives Cambodian nationality to Jolie, "an American born on 4 June 1975 in Los Angeles, USA".

The actress began her association with the country when she filmed Lara Croft: Tomb Raider at Cambodia's famous Angkor Wat temple.