Jolie, who has already served more than 10 years as goodwill ambassador for the U.N. High Commissioner for Refugees (UNHCR), is taking on a new role as special envoy for large-scale crises that cause huge numbers of civilians to flee their homelands.

She is expected to deal with complex emergencies and protracted crises including Afghanistan and Somalia that have driven millions of refugees into neighboring countries where they remain for years due to the lack of a political solution.

"UNHCR is pleased to announce today that Angelina Jolie will take on a new and expanded role for the U.N. refugee agency as Special Envoy of High Commissioner Antonio Guterres," UNHCR spokesman Adrian Edwards told a news briefing in Geneva.

The Oscar-winning Jolie was due to be named Special Representative on the Afghan refugee crisis last October, but there was no final agreement.

"In her new role, she is expected to focus on large-scale crises resulting in the mass displacement of people, to undertake advocacy and represent UNHCR and Mr. Guterres at the diplomatic level," Edwards said.

This can include "conveying messages to governments" and emphasizing the need to adhere to human rights law, he added.

The "Tomb Raider" star has already made 40 field visits to remote hotspots in more than 20 countries, including Afghanistan, Bosnia, Haiti, Iraq and Sudan. She has donated at least $5 million which has helped build schools in Kenya and Afghanistan, the UNHCR said.

"Quite honestly, I don't think you need a rocket scientist to see the benefits that she is bringing in terms of the attention that she's getting for the plight of the world's displaced," he said.

She will be making a fresh field visit in coming days but he declined to identify the region or country for security reasons.

"This is an exceptional position reflecting an exceptional role she has performed for us," he said.

A year ago Jolie went to Tunisia's border with Libya to meet African migrants and others fleeing war. In June she accompanied Guterres to the Italian island of Lampedusa to support migrants who crossed the Mediterranean to escape from Libya.

"My personal experiences with UNHCR have been moving, sometimes heartbreaking, but always rewarding and unforgettable," Jolie told UNHCR's Executive Committee in October

Her interest in humanitarian affairs piqued in 2000 when she went to Cambodia to film the adventure movie Tomb Raider.

She first approached the U.N. Children's Fund (UNICEF)seeking an ambassadorial role helping women and children, but it found her "too edgy" at the time, UNICEF sources told Reuters.

Jolie, 36, and Brad Pitt, 48, one of the world's best known couples, are engaged to marry, ending a seven-year celebrity media dance over whether they will ever say "I do".

A spokesman for Pitt confirmed last Friday that the pair had agreed to wed after Jolie was photographed in Los Angeles wearing a large diamond ring, designed by Pitt. She has been married twice previously.

The couple, dubbed Brangelina by celebrity media, are raising six children together, three of whom are adopted, from Cambodia, Ethiopia and Vietnam.

(Additional reporting by Tom Miles, editing by Paul Casciato)

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