A surgical mask worn by Michael Jackson at his last ever rehearsal is being auctioned.

The silk fabric mask was reportedly worn by the late 'Thriller' star during his last ever run through of his 'This Is It' concert before he died of acute Propofol intoxication in June 2009.

The mask has already got bids of $20,000, and is expected to fetch up to $150,000 when bidding ends on April 30.

Nate D. Sanders Auctions claims the mask was personally designed by Michael and in its listing it says the item has ''visible traces of his make-up,'' and notes, ''a single dark strand of Jackson's hair accompanies the mask''.

The mask comes from one of Michael's former bodyguards, who swears by its authenticity.

The eccentric singer often wore surgical masks outdoors as a form of disguise and protection against breathing in smog.

Although Michael died before the first of his 50 'This Is It' shows in London, he could potentially tour again, with the help of new hologram technology that recently saw Tupac Shakur resurrected to perform at Coachella music festival in California.

Michael's brother, Jackie Jackson, said: ''It could have Michael - absolutely. Wouldn't that be wonderful? As a matter of fact, we had that idea two years ago for Michael's Cirque Du Soleil show.''