6:11 PM PT -- OpenAI's CEO Sam Altman tells TMZ ... “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. 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.”

Scarlett Johansson appears ready to go to legal war (again) -- only now, it's all about ChatGPT's newest voice sounding eerily similar to her ... and she says that's no coincidence.

The actress came out swinging Monday on the heels of OpenAI -- the creator of ChatGPT -- yanking their newest feature of their hottest commodity ... namely, suspending AI voices they recently trotted out, including one that many said sounded just like ScarJo.

They dubbed the new voice Sky ... and many felt it eerily mirrored Scarlett's AI character in 2013's "Her" -- where Joaquin Phoenix falls in love with a computer that sounds human.

As it turns out ... Scarlett claims that she was actually approached by OpenAI's head honchos in September -- including CEO Sam Altman -- who she says wanted to hire her to voice the current ChatGPT 4.0 model. SJ says she considered it ... but ultimately declined.

Fast-forward to December, and OpenAI's "Sky" was rolled out ... with just about everyone saying it reminded them of ScarJo -- and she thought so too, which is why she lawyered up.

Scarlett even says Sam leaned into the whole "Her" connection by tweeting "her" when the Sky voice was debuted a couple weeks ago ... which, to her, suggests they found a loophole in getting their own ScarJo -- namely, generating a voice or hiring someone else to come across just like her.

She released a statement saying ... "As a result of their actions, I was forced to hire legal counsel, who wrote two letters to Mr. Altman and OpenAl, setting out what they had done and asking them to detail the exact process by which they created the 'Sky' voice."

Scarlett goes on to say this ... "Consequently, OpenAl 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. I look forward to resolution in the form of transparency and the passage of appropriate legislation to help ensure that individual rights are protected."

In other words, she seems to be saying she scared OpenAI into yanking the feature -- although, OpenAI didn't acknowledge this in the press release for their decision ... and they even explicitly denied Sky intentionally being an explicit imitation of ScarJo/Her.

Clearly, Scarlett disagrees. We've reached out to OpenAI ... so far, no word back.