The red PVC pants, signed by the former Queen frontman, were snapped up by a buyer acting for trendy London eaterie the Hard Rock Cafe at Bonhams salerooms, Chelsea, west London.
The Cafe also also picked up Frank Zappa's 1966 Hagstrom Sunburst 12- string steel electric guitar for pounds 6,325.
But the biggest disappointment of the day was bidding for The Rolling Stones' mobile recording studio which failed to reach its reserve price of pounds 15,000.
The Leyland Daf 1970 custom-built van was used to record the group's albums Sticky Fingers and Exile on Main Street.However, an interested buyer who missed the auction may now step in.
Ted Owen, entertainments specialist for Bonhams said: "He thought the sale was on tomorrow. He is a private buyer."Reuse content