Britney Spears appears to be firing back at "Pretty Girls" collaborator Iggy Azalea, following a tweet that seems to blame the latter why the song flopped.

The "Womanizer" singer took to Twitter to write, "Can't wait to get back to Vegas. So thankful I have shows for the rest of the year to look forward to... #YouWantAPieceOfMe."

No names were dropped. However, the tweet was clearly referring to the "Black Widow" singer, who has decided to cancel her tour because she had a change of heart and felt like she deserves a break.

Spears currently has a multi-million residency, which she has extended for the next three months, at the Plane Hollywood Resort and Casino in Las Vegas. In addition, there's that hashtag which clearly points out to her track entitled "Piece of Me," as per a Billboard report.

The rumored feud began when the Australian rapper responded to fan saying that it was difficult to send a song up to the charts without additional promotion and television performances, E! News has learned. Azalea added that it was unfortunate she was only a feature.

The "Fancy" singer stood by her statement and said it was factual — it applies to any songs. What made her comment even more controversial was when she said that she didn't have to suck the woman's asshole 24/7 just to become her friend.

On top of her statement, she said that having a differing thought without it being bitchy or shady is possible and healthy. She also said that she was not getting it 100 percent right all the time.

Following the release of the '80s-inspired music video, Spears and Azalea performed "Pretty Girls" together at the 2015 Billboard Music Awards.

The song ranked 29^th on the Billboard Hot 100 charts. It dropped out of the top 40 three weeks after, The Financial Express reported.