It's an attorney's worst nightmare: an internationally renowned American pop star with millions of fans is sued by an established fashion designer from Australia. Both women share an almost identical name, leading to a complex and closely watched international trademark lawsuit.

Australian clothing designer Katie Perry filed suit against American superstar Katy Perry, alleging trademark infringement. The Australian Perry, who established her clothing brand in 2006, registered her trademark in 2008, a year before Katy Perry (born Katheryn Hudson) achieved international fame with her breakout hit, "I Kissed a Girl."

In 2009, fashion designer Katie Perry reached out to Katy Perry’s representatives, hoping to establish an agreement about the use of their shared name. Negotiations went nowhere, leading to a legal battle that has now lasted over five years.

Katie Perry won her initial trademark infringement lawsuit in 2023 in Australia. However, the decision was overturned upon appeal in 2024. The High Court of Australia, equivalent to the U.S. Supreme Court, is currently reviewing the case as of 2025. The plaintiff’s attorneys argue that the appellate court erred by relying on flawed reasoning regarding fame, commercial impact, and the protection of local trademarks.

The Australian designer asserts that her trademark rights were violated by Katy Perry’s sale of branded clothing during tours in Australia. The key legal question for the High Court is whether the fame of the American singer at roughly the same time as the Australian designer affects trademark infringement standards under Australian law.

Trademark infringement laws differ somewhat between the United States and Australia, though both systems heavily rely on precedents. A notable Australian example is the famous "Burger King" case. When the franchise Burger King entered Australia, a local business already held the "Burger King" trademark, forcing the franchise to rename itself "Hungry Jack’s."

In the United States, trademark infringement involves "the unauthorized use of a trademark or service mark on or in connection with goods and/or services in a manner likely to cause confusion, deception, or mistake about the source of the goods and/or services."

Australian trademark infringement similarly occurs when "a registered trademark is infringed if a person uses, as a trademark, a sign substantially identical with, or deceptively similar to, the registered trademark in relation to the goods or services for which the trademark is registered."

Notably, Australia offers broader protections for "well-known trademarks." Under subsection 120(3) of Australia's Trade Marks Act, the registered owner of a well-known trademark can pursue infringement actions even when the contested mark is used on goods or services unrelated to those covered by the original trademark, provided the use creates confusion.

Both countries also adhere to the World Trade Organization’s Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS). In U.S. federal courts, a well-known trademark owner can pursue infringement under Section 43(a) of the Lanham Act.

Courts examine various factors to determine infringement, including the similarity of the marks, relatedness of goods and services, strength of the plaintiff's trademark, marketing methods, consumer confusion, intent, actual confusion, and the potential for expansion into new product lines.

Ultimately, the crux of this international legal battle hinges on determining whether Katy Perry’s global celebrity status and subsequent branding activities infringe upon Katie Perry’s registered Australian trademark rights. The High Court's forthcoming decision will set a critical precedent regarding the balance between local trademark protections and global celebrity branding.