On the eve of a major auction of his work at Sotheby's in London, Damien Hirst's manager says the controversial Brit artist has become a billionaire - while one of the world's foremost art critics says he's little more than a no-talent huckster. Hirst's business manager Frank Dunphy says he is now the "biggest dollar earner in the history of art" with a net worth of $1 billion, which would make him one of the richest men in the UK, the London Times reports.

Dunphy says that in addition to his art, Hirst has invested heavily in real estate, and now has so many properties he's lost track of the exact number, which he estimates at between 30 and 40. These include a $5 million country house in Gloucester and a couple of Georgian houses in London's chic Mayfair district. If accurate, the $1 billion figure means Hirst's wealth has been vastly underestimated to date. The London Sunday Times 2008 Rich List calculated his fortune at only $350 million.

The Sotheby's sale today is expected to bring in at least $120 million. And like Picasso, Hirst says his signature alone is now worth a lot of money. "Someone in a gallery in New York told me the other day that my signature is worth $350," he tells the London Evening Standard. "It's actually something they can define. That means if I sign a check in a restaurant and it's for $250 the check is actually worth more than the bill comes to. On that level, yeah, maybe I am in the same position as Picasso. If you believe all that shit."

One person who emphatically does not believe "all that shit" is world-renowned art critic Robert Hughes. He has labeled Hirst's work "absurd" and "tacky commodities" in a new art world documentary airing in the UK later this month, the London Telegraph reports. Hughes singled out Hirst's famed shark in formaldehyde, entitled The Physical Impossibility of Death in the Mind of Someone Living, for particular criticism, calling it "the world's most overrated marine organism."

As we reported earlier this month, Hirst himself has said he's sick of some of the work he's become rich and famous for and plans to pursue other artistic avenues. In any case, Hirst has at least garnered the admiration of Vanity Fair which ranks him at No. 31 on their new list of the world's most powerful and influential people, putting him ahead of moguls like Sumner Redstone.