WASHINGTON (AFP) ― A lawyer in Philadelphia is gearing up to sue Led Zeppelin for allegedly pilfering another band’s music when it composed and recorded its 1971 classic “Stairway to Heaven.”

Contacted by AFP on Tuesday, Francis Alexander Malofiy confirmed a report in Bloomberg Businessweek saying a copyright lawsuit is in the works, but declined to give details.

According to the magazine, the plaintiffs in the pending case allege Led Zeppelin lifted the opening riffs of “Stairway to Heaven” from a 1968 instrumental called “Taurus” recorded by the Los Angeles psychedelic band Spirit.

The plaintiffs include Spirit’s founding bassist Mark Andes and the trust that manages royalties for the band’s guitarist Randy California, who died in 1997.

Spirit and Led Zeppelin shared the stage during a U.S. tour in 1969.

Led Zeppelin guitarist Jimmy Page is said to have started writing “Stairway to Heaven” in 1970 in a remote cottage in Wales. Released the following year, it’s widely regarded as one of the greatest rock tunes of all time.

Bloomberg Businessweek said the eight-minute song had earned $562 million as of 2008.

Earlier this month Led Zeppelin unveiled two previously unheard recordings ahead of the re-issue in June of its first three albums. Page, now 70, meanwhile scotched rumors of a reunion concert.