Michael Jacksons untimely death at 50 yesterday, apparently from cardiac arrest (see ARTINFO's tribute here), caught the world by surprise. Not least the auction world.

In a rarefied league with items related to Elvis Presley and Marilyn Monroe, Jackson memorabilia was already highly collectible. Now it will become even more so, according to Darren Julien, chief executive of the Beverly Hills, Calif.–based Julien’s Auctions.

Julien is well versed in Jacksonabilia. His company nearly put up 1,400 Jackson items for auction earlier this year, before the singer changed his mind and sued to cancel the sale. Several other Jackson-related items will be part of Julien’s Summer Sale today and tomorrow in Las Vegas, including a concert T-shirt from his Michael Jackson Victory Tour and a signed belt.

Christie’s International has offered a number of Jackson memorabilia items in recent years, not always with great results. In December 2006, a color photograph of the singer’s high school class from 1973 went for $180, below it pre-sale estimate of $300 to $500. A ballpoint pen drawing of Elvis by Jackson sold for $250 in November 2007, also falling short of its estimate, $400 to $600.

“It is too early to ascertain the effect of yesterday's news on the value of Michael Jackson memorabilia; this will be felt over time and dictated by supply of items to the market,” a Christie’s International spokesperson said in a statement today.

But if eBay is any indication, interest in Jackson-related keepsakes are already on the rise, albeit at the low end of the market. From June 11 to 24, only six items with “Michael Jackson” in their description were sold in the online auctioneer’s “Art” category, never more than one a day. Yesterday, beginning in the afternoon — when news that Jackson was ill began to circulate — there were 12 sales, the largest of which was a framed poster from the Thriller album that went for $39.95. So far today, eight items have been sold, the most expensive of which was an oil painting on canvas entitled King Michael Jackson that is an apparent copy of a 1995 work by Norman Oak. It went for $138.

Items still available range from a painting by an unnamed artist portraying the singer in the 1980s, listed at a starting price of $49,000, down to a print of Jackson in court in 2005 starting for a penny.

Jackson’s career had been dampened in recent years, especially following his trial in 2005 on child molestation charges, even though he was acquitted. The singer had planned a major comeback tour starting next month to help pay down his debt and help revitalize his image.