Rockers Ozzy Osbourne and John Mellencamp object to groups appropriating their music at anti-gay events.

Fifty-nine-year-old Mellencamp has written to the National Organization for Marriage (NOM), the nation's most vociferous opponent of gay marriage, asking it to stop using his song Pink Houses at its anti-gay marriage rallies.

“Please be aware that Mr. Mellencamp's views on same sex marriage and equal rights for people of all sexual orientations are at odds with NOM's stated agenda,” the letter, written by Mellencamp's publicist Bob Merlis, reads in part.

“We would encourage you to find music from a source more in harmony with your views than Mr. Mellencamp in the future,” Merlis added.

Osbourne released a statement on Friday objecting to the anti-gay Westboro Baptist Church's use of his song Crazy Train on the steps of the United States Supreme Court.

“I am sickened and disgusted by the use of Crazy Train to promote messages of hate and evil by a church,” Osbourne said.

The church – known for using the slogan “God Hates Fags” – is defending before the court its right to protest the funerals of U.S. soldiers.