Dozens of artists including Roger Waters called Monday on Radiohead to cancel a concert in Israel, saying the band known for its left-wing politics should join Palestinian activists' boycott calls.
The English experimental rock icons are scheduled to play in Tel Aviv on July 19, closing a tour that includes premier festivals Coachella and Glastonbury.
Radiohead has played benefits for Tibetans' rights and Amnesty International and the battle against climate change.
"Since Radiohead campaigns for freedom for the Tibetans, we're wondering why you'd turn down a request to stand up for another people under foreign occupation," the letter said.
"In asking you not to perform in Israel, Palestinians have appealed to you to take one small step to help pressure Israel to end its violation of basic rights and international law.
"Surely if making a stand against the politics of division, of discrimination and of hate means anything at all, it means standing against it everywhere -- and that has to include what happens to Palestinians every day," it said.
Waters, the former Pink Floyd member and creative force of "The Wall," has long been outspoken on Israel.
Other signatories included novelists Alice Walker and Hari Kunzru, Thurston Moore of US alternative rock pioneers Sonic Youth and Nick Seymour of Australian rockers Crowded House.
Retired bishop and Nobel Prize-winning anti-apartheid campaigner Desmond Tutu also signed the letter.
A cultural boycott campaign against Israel has had mixed success. Stevie Wonder, Carlos Santana and Lauryn Hill have scrapped shows in Israel but plenty of major names including Paul McCartney, the Rolling Stones, Elton John and Bon Jovi have performed in recent years.
Israel's defenders have denounced the boycott campaign as hypocritical, saying the democratic country has been singled out when some prominent musicians are willing to play in dictatorships.
Radiohead has not played Israel since 2000. That concert was part of a now-legendary Mediterranean swing where Radiohead previewed songs from "Kid A," often called the band's masterpiece, which were swapped online before the album's release.