“Thought it was done, but I guess it’s never really over.”

When international pop superstar Katy Perry sang these lyrics five years ago, she may have been predicting her long-running trade mark battle with an Australian fashion designer.

Katie Jane Taylor sued Perry in October 2019, more than 10 years after the performer behind hits like Firework, Roar and Dark Horse started selling merchandise, including clothing, under her own name.

The designer had sold her own line of clothing under the Katie Perry label since 2007 – using her birth name.

She achieved a further legal win in the case on Friday with the High Court allowing her lawsuit against Perry to continue by granting her application for special leave.

The decision allows Taylor to try overturn a Full Federal Fourt judgment from November that the US singer, whose real name is Katheryn Hudson, did not infringe the Katie Perry mark by selling clothing during her 2014 Prism tour in Australia.

Three judges from the Full Court had thrown out Justice Brigitte Markovic’s 2023 findings that Perry’s firm Kitty Purry had infringed the mark.

Taylor’s own trademark would be deregistered, the judges said.

On Friday, Taylor’s barrister Christian Dimitriadis SC said the appeal judges had erred in their interpretation of Australian trademark law.

The logic that celebrities could use their reputation to expand into clothing could also apply and affect Australians selling products ranging from whisky and wine to perfume and invisible dental braces, the judge said.

Dimitriadis said Taylor had the misfortune of choosing a trademark similar to someone who became famous and then proceeded to sell clothing in Australia, knowing she was infringing that mark.

The Full Court’s decision to deregister the Katie Perry brand because it found Taylor had applied for the trademark knowing of the US singer’s reputation was incorrect, he said.

Perry’s barrister Matthew Darke SC unsuccessfully argued that the High Court should not hear the case as it did not involve an important question of law.

Taylor declined to comment on the case after the hearing.

The High Court will hear the full appeal at a later date.

-AAP