"They should be arriving in Lesotho in the third week of June, either on the 16th or on the 17th," said an official who works closely with Prince Harry’s Sentebale, a charity for AIDS orphans.
The princes are then scheduled to travel to South Africa for England's third World Cup match against Algeria in Cape Town.
The visit will be Prince William's first trip to the mountainous kingdom, which is completely surrounded by South Africa. Officials said he will visit some of the sites where his brother's charity runs projects.
Prince Harry was last in Lesotho in 2008. He helped build a school in Botha-Bothe in northern Lesotho, where his mobile phone was snatched by a local at a nightclub. The royal did not press charges.
The princes' trip is also scheduled to include a stop in Botswana, where Prince William is involved with wildlife charity Tusk Trust.
Prince William, who is the president of the English Football Association, is expected to watch England's first group C match against the United States on June 12 in Rustenburg.
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