Orlando Bloom's first screen appearances were in the BBC TV show Casualty
British actor Orlando Bloom is to be a goodwill ambassador for the UN children's organisation Unicef.
Unicef said the star of Lord Of The Rings and Pirates Of The Caribbean would work to help poor children and raise awareness of the organisation.
The 32-year-old's first task will be to film an appeal about the importance of clean water supplies.
Past ambassadors include David Beckham, Audrey Hepburn, Roger Moore, Vanessa Redgrave, Shakira and Ryan Giggs.
Bloom, regarded as one of the world's most popular male celebrities, said he wanted to be an active ambassador for Unicef.
He said: "I look forward to working with Unicef as they continue to make the world a better place for children."
Bloom, who was born in Canterbury, Kent, has been involved with the organisation since 2007, when he visited schools and villages in a remote area of Nepal to support sanitation and education programmes.
He has also visited Moscow and Sarajevo on behalf of Unicef.
Unicef's executive director, Ann M. Veneman, said the work of high-profile goodwill ambassadors helped "to build momentum to improve the lives of children around the world".
She added: "We are proud to have Orlando Bloom as one of the strong voices for vulnerable children."
His latest film, a romantic anthology called New York, I Love You opens in the US on Friday.