Singer Katy Perry has successfully appealed against a trademark decision over her name, after being sued by an Australian designer who sells clothes under her birth name Katie Perry.

Three appeals judges on Friday overturned a court decision last year that favoured Katie Taylor over merchandise sold by the pop star during a 2014 tour of Australia.

The judges said Perry had been using her name as a trademark five years before Taylor started her business, adding that by that time, Perry had attained an "international reputation" in entertainment.

The judges also cancelled Taylor's trademark registration on Friday.

Taylor had likened her legal battle with Perry to "David and Goliath". She told the Sydney Morning Herald after Friday's ruling that she was "devastated" with the case outcome.

The appeals judges said it was "unfortunate" that the case pitted two enterprising women who used their names as trademarks but were unaware that the other existed.

“Both women put blood, sweat and tears into developing their businesses,” the judges said.

“As the fame of one grew internationally, the other became aware of her namesake and filed a trademark application,” they said.

The judge who ruled in favour of Taylor last year referenced one of Perry's biggest hits in her decision: "This is a tale of two women, two teenage dreams and one name".

Friday's ruling comes as Perry prepares for her Lifetimes world tour in early 2025 to support her comeback album 143.