The Grammy winner, who has been fighting to move Billy, dubbed "the world's saddest elephant", to a sanctuary for 15 years, is pushing back after it was announced the elephants are set to be sent to another zoo in Oklahoma.

"Billy has been locked up since 1989," Cher wrote in a statement.

"Tina was held captive in a private zoo prior to being placed in the LA Zoo. They have been through hell.

"Billy and Tina have served their time in confinement. They deserve the chance to live out their lives in peace and dignity."

The If I Could Turn Back Time singer also filed a declaration in support of an emergency motion that would allow LA Mayor Karen Bass to hear an alternative offer to move Billy and Tina to a sanctuary.

Cher, who co-founded the Free the Wild Charity, said in her declaration, "I am asking for you to put the decision on hold until we can further investigate the possibility of transferring Billy and Tina to a sanctuary.

"Sanctuaries offer acres of soft, natural terrain, trees, rivers and freedom. Free The Wild has helped make this a reality for elephants like Kaavan, who we moved from miserable isolation in a zoo to a thriving sanctuary in Cambodia. We know what sanctuary looks like. We know it heals."