Credit: Ed MilesThe ongoing copyright-infringement case involving Led Zeppelin‘s “Stairway to Heaven” has prompted Robert Plant to pull out of a scheduled June 19 appearance at the 2016 Meltdown Festival in London.

A message posted on Plant’s Facebook page explains that the singer had to cancel because he’s a defendant in the court case, which is scheduled to begin proceedings on June 14 in Los Angeles.

Plant’s withdrawal from the show — dubbed “The Boat We’re In” — as well as other unrelated factors have led the organizers to cancel the event. The concert had been intended to raise money for the British Red Cross’ refugee awareness campaign, and was tied in with a recently released charity EP called The Long Road, to which Robert contributed a cover of the Elbow song “Blanket of Night.”

Plant’s Facebook note explains, “Robert has been enthusiastic to help in any way to the increased awareness and support of so many powerless and distraught peoples. Therefore the opportunity afforded at [the] Meltdown [festival] was an event that Robert was passionately drawn to.”

According to The Hollywood Reporter, Plant’s fellow Led Zeppelin members Jimmy Page and John Paul Jones also will be attending the trial, which is being held to determine whether Page and Plant partly copied the Spirit song “Taurus” when they co-wrote “Stairway to Heaven.” The band’s attorneys recently accused lawyers for late Spirit frontman Randy California‘s estate with attempting to taint the jury pool by falsely claiming that Led Zeppelin’s members were trying to avoid taking part in the trial.

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