Singer Elton John had some harsh words for chart rival Madonna during an interview for Australian TV.

“She's such a nightmare,” he told Molly Meldrum on Sunday Night. “Sorry, her career is over. Her tour has been a disaster and it couldn't happen to a bigger c**t.”

Sir Elton also said his ex-friend has been “horrible” to Lady Gaga, who is grandmother to his son Zachary.

Madonna has several times suggested that Lady Gaga's gay anthem Born This Way was a knock off of her 1989 hit Express Yourself. She told ABC's 20/20 that the song “felt reductive.”

“If Madonna had any common sense, she would have made a record like Ray of Light, stayed away from the dance stuff, and just been a great pop singer and made great pop records, which she does brilliantly. But no, she had to prove that she was like … And she looks like a f**king fairground stripper.”

(Watch the entire interview at Sunday Night's official website.)