May 20 - Scarlett Johansson on Monday accused OpenAI of creating a voice for the ChatGPT system that sounded "eerily similar" to the actress after she declined to voice the chatbot herself.

Johansson made the comments in a statement released hours after the artificial intelligence company said it was taking down the voice, called 'Sky.'

OpenAI CEO Sam Altman said in a statement emailed to Reuters on Monday that Sky's voice was not an imitation of Johansson, but belonged to a different professional actress.

"The voice of Sky is not Scarlett Johansson's, and it was never intended to resemble hers. We cast the voice actor behind Sky’s voice before any outreach to Ms. Johansson," Altman said.

"Out of respect for Ms. Johansson, we have paused using Sky’s voice in our products. We are sorry to Ms. Johansson that we didn’t communicate better."

The fight over rights to actors' voices and images has become a focus in Hollywood as studios consider how to use AI to create new entertainment and as the computer-produced images and sounds become difficult to distinguish from those of humans.

Johansson in the statement said Altman had approached her last September and offered to hire her to voice a ChatGPT voice -- an offer she declined.

"Nine months later, my friends, family and the general public all noted how much the newest system named 'Sky' sounded like me," she said.

"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 added that Altman had "insinuated that the similarity was intentional" by tweeting a reference to "her," the 2013 movie about a man who develops a relationship with an AI assistant voiced by the actress.

Johansson's note was published by journalists from NPR and other news outlets. Her publicist also shared it with Reuters.

OpenAI did not immediately respond to a request for comment after Johansson's statement. She said that she had hired legal counsel to ask about the process of creating the voice.

OpenAI showed off its newest AI model, called GPT-4o, last week, with audio capabilities that let users speak to the chatbot and obtain real-time responses, marking a significant advancement in more realistic sounding AI conversations. (Additional reporting by Rishabh Jaiswal and Kanjyik Ghosh in Bengaluru; writing by Peter Henderson; editing by Noel Randewich and Sam Holmes)