Ailing 81-year-old ex-wife of late TV legend JOHNNY CARSON claims she was sweet-talked into marrying a DOPE FIEND – and now he’s threatened to kill her!

Joanne Carson, whose nine-year marriage to the “Tonight” show icon ended in 1972 during the height of his career, suf­fers from multiple health problems and is confined to her home on a breathing appa­ratus.

In court papers obtained exclu­sively by The ENQUIRER, she claims her hubby Richard Rever, 56, wants her dead so he can grab her loot. Joanne received $100,000 a year in alimony from Carson and turned that into an estimated $30 million fortune through wise investments.

“Johnny would be spinning in his grave if he knew about the nightmare poor Joanne is going through,” said a close friend. “She raised his three boys from his first marriage and he loved her dearly.”

Joanne has slapped Rever with a restraining order, claiming that he has a long history of drug abuse. And when she asked him to sign a postnuptial agreement on Feb. 13, she claims he dis­connected her oxygen tube and she nearly suffocated.

When Joanne tossed Rever out of her $10 million Bel-Air man­sion, she says he left with at least $50,000 worth of her personal memora­bilia, and racked up $16,000 in charges on her American Ex­press card. Then, she claims, Rever tele­phoned her and said: “You are dead meat!”

Rever’s rep says Joanne’s claims are not true, her restraining order was never served and that she lev­eled the allegations against him because she was “very upset” when he filed for divorce.

But her pal said: “Joanne is ter­rified of Richard. She’s afraid that he’s after her money, and he won’t stop until she’s dead!”