A pair of Elton John's famous heart-shaped glasses were stolen from a museum yesterday.

According to TMZ, the shades were taken from the Rock 'n' Soul Museum in Memphis, even though the case that contained them was locked. As of now, nobody knows how the thief managed to break into the display and walk away with the glasses.

"Museum honchos say someone had to use tools in order to jimmy the lock," reports TMZ.

John wore dozens of different styles of glasses over the years, especially in the '70s, when he was at the height of his fame and his image helped sell his music. From live shows to TV appearances, John's glasses -- no matter what the style -- were almost as ubiquitous as his presence on the pop charts at the time.

Apparently the museum's surveillance cameras didn't capture any footage of the thief in action, but the case was searched for fingerprints. A museum director noted that the glasses are valued at about $2,000.

John recently celebrated the 45th anniversaries of both his second album (the self-titled one that included "Your Song" and helped break the artist in the U.S. and across the globe) and his first world tour, which capitalized on the success of that Top 5 LP.

See Elton John and Other Rockers in the Top 100 Albums of the '70s

See Elton John in Rock's Nastiest Feuds