A one-of-a-kind collaborative painting that the Beatles worked on during their 1966 visit to Tokyo has been unboxed after spending over 20 years under its owner's bed -- and now it's headed for the auction block.

The painting, titled 'Images of a Woman,' gave the Fab Four something to do while they were holed up in the Tokyo Hilton during a tour stop. Forced to dart between the hotel and the concert venue under tight security during the height of Beatlemania, the band members sat down at a canvas and came up with the only painting to bear all four of their signatures -- a colorful image that they donated to the chairman of their Tokyo fan club.

The painting was auctioned off by the original owner's wife in 1989, ending up in the hands of a collector (and huge Beatles fan) named Takao Nishino who paid the equivalent of half a million dollars for it -- only to run out of wall space three years later. After purchasing a special humidity-controlled frame, he decided to box it up and slide it under his bed, where it's mostly stayed for the last 20 years.

Says Nishino now, "Originally, I thought it might be best kept as a piece of Japan's cultural heritage; it has never left Japanese soil in 46 years. But the Beatles phenomenon was and remains a global one." There should be no shortage of willing bidders for the painting on Sept. 14, when it will be sold alongside celebrity memorabilia that includes Frank Zappa artwork and a leather jacket that belonged to the Notorious B.I.G.