The 33-year-old singer posted a snide tweet believed to be about the rapper after the 'Fancy' hitmaker hinted the pair's collaboration 'Pretty Girls' failed to achieve chart success because Britney wouldn't promote it properly.
Referring to Iggy's US 'Great Escape' tour - which she recently cancelled because she wanted ''a break'' - she wrote: ''Can't wait to get back to Vegas. So thankful I have shows for the rest of the year to look forward to... #YouWantAPieceOfMe (sic).''
The 25-year-old star - who got engaged to basketball player Nick Young earlier this month - had made her comments after a Twitter user suggested the single the pair recorded had ''flopped a little bit''.
She responded: ''its difficult to send a song up the charts without additional promo and tv performances etc. unfortunately im just featured...
''i would have enjoyed performing it alot, i think it got off to a powerful start. but you need content to compete in 2015. (sic)''
Iggy returned to the social media site later in the day to respond to Britney's fans who criticised her for her comments, insisting the pair are ''genuine friends''.
She added: ''My comment is factual, it applies to any song. I dont have to suck the womans a*shole 24/7 to be her friend, do i? bye girls
''Genuine friends have genuine opinions. Its possible & healthy to have a differing thought without it being b***hy or shade. (sic)''
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