A court in Japan has ruled that the human voice has legal protection after a landmark case involving a well known actor and a TikTok account whose AI-generated videos, he claimed, had cloned his “lustrous” baritone voice.

Tokyo district court said on Wednesday that voices enjoy the same protection as publicity rights, at the end of a closely watched legal action brought against TikTok by Kenjiro Tsuda – best known for voicing the character Kento Nanami in the anime Jujutsu Kaisen.

But the court dismissed Tsuda’s request that the operator of TikTok remove the videos, noting that the user had deleted them soon after the suit was filed last November. “The unauthorised use of a performer’s voice … can be considered an infringement on publicity rights,” said the presiding judge, Aya Takahashi.

The lawsuit is believed to be the first in Japan seeking to defend an individual’s vocal identity against AI-generated copies. Japan’s voice actors, many of whom achieve star status through their “appearances” in anime, are increasingly worried that AI mimicry is threatening their livelihoods and the industry as a whole.

An actor’s voice “is the result of years of rigorous training and apprenticeship”, Yuko Sasaki, executive director of the Japan Actors Union, said ahead of the ruling.

Tsuda, 55, claimed that the 188 TikTok videos uploaded on an anonymous account between July 2024 and September last year had been narrated by a “deep” and “lustrous” voice that could only be his. In response, the platform argued that the videos contained a “generic male voice” and that any perceived similarities to Tsuda’s voice were highly subjective.

The verdict is the first in which a Japanese court declared that the human voice is protected under publicity rights, a reference to the ability to control and profit from aspects of an individual’s identity, in Tsuda’s case his distinctive voice.

The protection applies “if the purpose of using the voice is exclusively to take advantage of its commercial appeal”, Takahashi said, describing a voice to be “as symbolic of one’s personality as portraits are”.

The TikTok account, whose picture resembled Tsuda’s Jujutsu Kaisen character, combined images and AI-generated speech about urban legends, the occult and conspiracy theories.

At one point, the account had more than 200,000 subscribers and, according to the legal complaint, the clips would have earned its owner between ¥500,000 (£2,395) and ¥75,000 in monthly revenue, the Kyodo news agency said.

Describing the content as “sordid”, Tsuda’s legal team claimed the account had only attracted attention because it had cloned the “attractive voice of a popular actor”.

TikTok said in a statement that it would “respect the court’s judgment while considering what steps to take after scrutinising [the ruling’s] details”.

“We will continue to sincerely work on the balance between technology development and rights protection,” it added.

In 2024, actors in Japan launched a campaign called “No More” to oppose the unauthorised use of their faces and voices in AI-generated content.

With reporting by Agence France-Presse