Mr Altman approached the 39-year-old Oscar nominee to voice the current ChatGPT 4.0 system last September but Johansson declined for personal reasons, she said in a statement.
"He told me that he felt that by my voicing the system, I could bridge the gap between tech companies and creatives and help consumers to feel comfortable with the seismic shift concerning humans and AI. He said he felt that my voice would be comforting to ."
Even though she declined the offer, nine months later, Johansson's attention was drawn to how much OpenAI's Sky voice sounded like her.
"When I heard the released demo, I was shocked, angered and in disbelief that Mr Altman would pursue a voice that sounded so eerily similar to mine that my closest friends and news outlets could not tell the difference," Johansson said.
On 13 May, Mr Altman posted the word "her" on X, which Johansson said was a sign the similarity was intentional. The actress claimed it was a reference to a 2013 film - called Her - where she voiced a chat system that forms an intimate relationship with a human, played by Joaquin Phoenix.
Mr Altman's post has now been seen by more than 10.2 million and remains on his X feed.
"Two days before the ChatGPT 4.0 demo was released, Mr Altman contacted my agent, asking me to reconsider. Before we could connect, the system was out there."
OpenAI has now paused the controversial voice "out of respect for Ms Johansson", according to Mr Altman in a statement on Tuesday. The company offers five voices that can speak generated answers through its ChatGPT service.
However, the tech giant denied Sky was ever based on the actress's voice.
"The voice of Sky is not Scarlett Johansson's, and it was never intended to resemble hers," said Mr Altman.
"We cast the voice actor behind Sky's voice before any outreach to Ms Johansson."
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In a blog post, the company detailed its process for choosing voice actors, saying it received more than 400 submissions from screen and voice actors when it was creating its voices in 2023.
It said it looked for a range of voices that were from diverse backgrounds, feel "timeless", were "approachable", "warm, engaging, confidence-inspiring, charismatic voice with rich tone" and were easy to listen to.
After selecting five actors in May 2023, the company said it flew them to San Francisco for recording sessions and then launched their voices into ChatGPT in September 2023.
The artificial intelligence (AI) company said it finds deepfakes unacceptable and is working to prevent its synthetic voices from copying those of real . Deepfakes are digital imitations of made to seem realistic using AI.
Last September, I received an offer from Sam Altman, who wanted to hire me to voice the current ChatGPT 4.0 system.
He told me that he felt that by my voicing the system, I could bridge the gap between tech companies and creatives and help consumers to feel comfortable with the seismic shift concerning humans and AI.
He said he felt that my voice would be comforting to .
After much consideration and for personal reasons, I declined the offer.
Nine months later, my friends, family and the general public all noted how much the newest system named "Sky" sounded like me.
When I heard the released demo, I was shocked, angered and in disbelief that Mr Altman would pursue a voice that sounded so eerily similar to mine that my closest friends and news outlets could not tell the difference.
Mr Altman even insinuated that the similarity was intentional, tweeting a single word "her" - a reference to the film in which I voiced a chat system, Samantha, who forms an intimate relationship with a human.
Two days before the ChatGPT 4.0 demo was released, Mr Altman contacted my agent, asking me to reconsider. Before we could connect, the system was out there.
As a result of their actions, I was forced to hire legal counsel, who wrote two letters to Mr Altman and OpenAI, setting out what they had done and asking them to detail the exact process by which they created the "Sky" voice. Consequently, OpenAI reluctantly agreed to take down the "Sky" voice.
In a time when we are all grappling with deepfakes and the protection of our own likeness, our own work, our own identities, I believe these are questions that deserve absolute clarity.
