‘Pretty Girls’ is a collaboration both Britney Spears and Iggy Azalea would rather forget.

The Aussie rapper and American songstress have been embroiled in something of a Twitter battle over the song’s failure to top the charts.

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Speaking to a fan on Twitter over the weekend, 25-year-old Azalea shared her personal opinion as to why the song didn’t take off.

“It’s difficult to send a song up the charts without additional promo and TV performances, etc. Unfortunately, I’m just featured [on the track],” she said.

“I would have enjoyed performing it a lot. I think it got off to a powerful start, but you need content to compete in 2015.”

Several media outlets interpreted this as a dig at Spears, but Azalea used some, ahem, colourful language to deny this.

But the feud did not end there. Spears felt compelled to weigh in too, but her response was more of a personal attack than a statement.

“Can’t wait to get back to Vegas. So thankful I have shows for the rest of the year to look forward to,” Spears wrote on Twitter, referring to Azalea’s decision to cancel her tour earlier this year.

“#YouWantAPieceOfMe,” Spears added, referencing her 2007 hit song ‘Piece of Me’.

Azalea ended the debate by saying there was no “beef” between her and Spears, despite the media’s best efforts to suggest a conflict.

“We remain friends and I haven’t said anything negative at all about her. Does wishing we had promoted a single more make me the bad guy?” Azalea said on Twitter on Wednesday.

“I’m over it. Women in music are not the same as a teen drama. Stop making us all out to be. We are business women and artists. Not mean girls.”