Registration for the chance to gain tickets to the Led Zeppelin tribute concert for the late Ahmet Ertegun will be extended two days, organizers announced Friday. During a 12-hour period on Thursday alone, nearly 90 million attempts were made to register for the ticket lottery.

Well above 25 million people have reportedly registered for the Nov. 26 concert in London. The venue, the O2 Arena only holds 20,000. Approximately 850 tickets, which will sell for $2,000 and up a piece, have been set aside for U.S. corporate interest, according the organizers. Regular tickets will sell for about $250 each, of which there will only be about 18,000 available.

“The Web site has been receiving over five million hits per hour since the press announcement 24 hours ago,” Harvey Goldsmith, the benefit concert organizer, told Billboard. “The service provider is doing their best to keep the site running and has moved it to a server on its own.”

Registration has been extended from a midday on Sept. 17 to midday on Sept. 19. According to published reports, the O2’s site crashed at least once, and the dedicated site for registration was averaging more than 80,000 requests per minute.

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Zeppelin will play “all the big numbers” in a “meaty” set of roughly two hours, Goldsmith told Billboard. The Who’s Pete Townshend, Bill Wyman, Foreigner’s Mick Jones and Paolo Nutini are also scheduled to perform.