They are two of the biggest stars in music. But lately, there's been little harmony between elton and madonna. Their war of words may have been sparked by an even bigger star, lady gaga. Here's the... See More
They are two of the biggest stars in music. But lately, there's been little harmony between elton and madonna. Their war of words may have been sparked by an even bigger star, lady gaga. Here's the breakdown on the he said/she said. ♪ Saturday night's all right for fighting ♪ Reporter: Forget saturday night. It was sunday night that was for fighting. Another round between elton john and madonna. At least for elton john, when he went on an australian tv show, and said this about his friendemy, madonna. Madonna's such a nightmare. Her career's over. I can tell you that. Her tour's been a disaster. Reporter: It's the latest round of the feud between the rocket man and the material girl, who seem to have become MODERN-DAY HATFIELDS and McCoy. She's been so terrible to gaga. Reporter: It may have started in january, when madonna slyly insulted gaga during an INTERVIEW WITH cynthia McFadden. It feels reductive. Is that good? Look it up. Reporter: But elton was having none of it. It turns out gaga is godmother to his son. And in days, he was lobbing insults at madonna at the golden globes. Madonna doesn't have . Those are fighting words. Accurate words. Reporter: Then, in an interview with "gma" right before the super bowl -- what would your advice beo madonna this year? Make sure you lip-sync good. Reporter: For her part, madonna has been able to express herself on the issue of gaga. She pointedly mashed up her song. With gaga's "born this way." ♪ I'm on the right track, baby I was born this way ♪ Reporter: As the tour as gone on, madonna made headlines for what has come off. If madonna had any sense, she would have stayed away with the dance stuff. But no. She had to prove -- and she looks like a fairground stripper. Oh, my. While we haven't gotten an official response from madonna to elton's latest comments. But one tells r s to elton's latest comments. But one tells ource says, she has nothing to prove to anyone, especially elton john.
This transcript has been automatically generated and may not be 100% accurate.