OpenAI says it will remove one of the voices used by ChatGPT after it was likened to Hollywood actress Scarlett Johansson.

Users spotted the similarity in the chatbot's "Sky" voice option, which reads responses aloud to users, when OpenAI showcased features of its new model.

The flirty, conversational upgrade to its AI chatbot drew comparisons to the 2013 film Her, starring the actress.

OpenAI said the voices available in ChatGPT's voice mode were "carefully selected through an extensive process spanning five months involving professional voice actors, talent agencies, casting directors, and industry advisors".

Set in the near-future, Her sees Joaquin Phoenix fall in love with his phone's operating system, which is voiced by Ms Johansson.

Director Spike Jonze said at the time the film was "not about technology or software", rather about finding love and intimacy.

In November, Ms Johansson reportedly took legal action against an artificial intelligence (AI) app which used her likeness without permission in an advert.

OpenAI said on Monday its "Sky" voice is not intended to be an "imitation" of the star.

"We believe that AI voices should not deliberately mimic a celebrity's distinctive voice," it said in a blog post.

The firm said it is "working to pause" the voice while it addresses questions about how it was chosen in a post on X, formerly Twitter.

Despite this, when OpenAI showed off its new model GPT-4o on 13 May, boss Sam Altman referenced the name of the film on X.

During the demonstration of its more human-like conversational abilities, the chatbot told an OpenAI staff member: "Wow, that's quite the outfit you've got on".

It also said "stop it, you’re making me blush” when complimented.

But amid memes and posts about ChatGPT - featuring gifs of the film's lonely protagonist Theodore Twombly - were also critical takes on the voice.

"This is giving such “female character as written by men” vibes," said one person on X.

"Why is she so obsequious and flirty?"

In its blog post, OpenAI said the five voices used by its chatbot were sampled from voice actors it partnered with.

Being multilingual and having an "approachable" or "charismatic" voice that "feels timeless" were among the characteristics it targeted to create the personalities.

The firm said it spoke individually with shortlisted actors about its vision for human interactions with AI, as well as the technology's capabilities, limits and risks, before deciding on the final voices.

The advanced voice features demonstrated at its spring update event have not been rolled out to ChatGPT users yet.

OpenAI says it will be made available to subscribers who pay for faster responses and priority access to new features in the coming weeks.