A legendary rock band is being accused of stealing parts of one of the most popular songs of the rock era. BloombergBusinessweek reports that a lawyer is preparing a lawsuit against Led Zeppelin, accusing the band of stealing parts of "Stairway to Heaven" from an instrumental called "Taurus" by the 1960s-1970s California band Spirit.

The attorney is representing the trust of the late Randy California, Spirit's frontman.

Bloomberg reports that "Stairway to Heaven" had earned at least $562 million by 2008.

The Spirit instrumental appears on the band's 1968 debut album.

Bloomberg reports: "For Led Zeppelin, 1968 was a big year. The band recorded its first album and flew to the U.S. to promote it with a series of shows. The day after Christmas, it played its first concert in America at the Denver Auditorium Arena. Led Zeppelin opened for Spirit."

The report adds: "Mark Andes, Spirit’s founding bassist, says he believes the members of Led Zeppelin heard 'Taurus' that day, beginning a process that would lead to its appropriation for 'Stairway.' 'Taurus' was a fixture of Spirit’s set at the time."

Said Andes: “It was such a pretty moment, and it would typically come after a big forceful number and always got a good response. They would have seen it in that context.”

The controversy involves the introductory notes of "Stairway to Heaven," which reportedly bear a strong resemblance to a guitar section around the middle of "Taurus."

Decide for yourself — here's an audio recording of "Taurus":