Assange, who is under house arrest in England fighting extradition to Sweden for questioning on an alleged sexual assault, filmed "The World Tomorrow" show from Britain.

Russia Today (RT) said in a news release that it would not release the guest list in advance, but said the first interview would prove controversial.

"We do not want to kill the buzz and the intrigue by revealing the name of the first guest," said RT editor-in-chief Margarita Simonyan.

"But I have no doubt that this particular guest and this interview will lead to calls to shut us down from some especially hawkish personalities who have little respect for freedom of speech," she added.

Australian-born Assange said in a statement he would be talking to people "who normally simply would not be given a voice on TV at all. What is fair to say is that the majority of what they have said to me they could not say on a mainstream TV network."

Russia Today is considered a key Kremlin exercise in image enhancement by critics. It is beamed to some 430 million subscribers worldwide and it also streams online.

Assange's new show will be broadcast simultaneously from Moscow and Washington DC, in English, Arabic and Spanish.

Assange said April 17 marks the 500th day since financial transaction firms like Visa, Mastercard and Paypal began to refuse working with Wikileaks after it published a raft of secret U.S. diplomatic cables in late 2010. The blockade has crippled the organization's ability to fund itself and continue its work.

(Reporting By Jill Serjeant; Editing by Bob Tourtellotte)

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