A global search has been launched to find one of the world's most iconic instruments—Paul McCartney's original Hofner bass guitar, BBC News reported.

The Lost Bass Project is appealing for information about what it describes as "the most important bass in history."

McCartney bought the instrument for £30 ($38) in Hamburg, Germany, in 1961, but it disappeared eight years later.

The hunt began after McCartney urged manufacturers Hofner to track down his beloved instrument.

The bass features in The Beatles' music of those years, including the hits “Love Me Do” and “She Loves You.”

Nick Wass is heading Hofner's search project and has joined forces with two journalists in trying to solve the "greatest mystery in the history of rock and roll."

He has collaborated extensively with McCartney and written a book about the missing Hofner 500/1 Violin Bass.

It is not clear what happened to the instrument, which was put away presumably after the Beatles finished filming Get Back in 1969, Wass said.