According to the auction house Nate D Sanders Auctions, the 'Thriller' hitmaker wore the mask while rehearsing for his 'This Is It' concert tour on June 24, 2009 which was his last ever rehearsal, reported TMZ.
The auction house claims the mask made of silk fabric was personally designed by Jackson and contains visible traces of his stage make-up along with a strand of his black hair.
One of MJ's former bodyguards was in possession of the mask, and swears by its authenticity. The singer famously wore surgical masks outdoors as a form of disguise. The auction ends April 30 and bidding has already reached USD 21,190. The auction house estimates the mask will sell for USD 50,000-USD 150,000.