Rebecca Ferguson says she once got berated by an A-list costar who she refuses to work with ever again — and while she didn’t name names … she did exclude two people, which has left the internet rife with guesses.

The actress dished this tea on the “Reign with Josh Smith” podcast — and she was responding to a question about a time when she owned her voice and took control of her situation … which led to this wild anecdote about a mystery fellow cast member.

Rebecca doesn’t ID them, nor does she implicate gender, but what she does say is that this actor she was working on the film with was absolutely horrible … allegedly yelling at her.

She says they were frustrated while they were doing scene work together, and they’d apparently hurl insults at Rebecca — openly questioning her acting methods and tenacity … while also noting they were the number 1 person on the call sheet. So, a big star basically.

Rebecca goes on to explain that nobody had her back on that set, but eventually … she found her own inner strength and told this actor to f*** off — and apparently even demanded that the person turn around while she recited her own lines.

In other words, she didn’t wanna be in the same space as this person, and it sounds like she put her foot down while shooting. The big question … who the hell is this awful person???

Like we said, Rebecca went out of her way to protect this celeb’s anonymity — but she did give some clues … including the fact this supposedly happened in the last 10 to 12 years. Of course, the internet is rife with speculation on which costar this could possibly be.

We should note … RF explicitly said it wasn’t Hugh Jackman and it wasn’t Tom Cruise. Technically — with the parameters she’s described — there’s only a select few actors it could possibly be We’re not gonna name anybody and fuel speculation … but folks seem to know who the options are here, guy or girl.

One person who’s stepped forward to seemingly distance himself from this drama is The Rock — who starred opposite Rebecca in 2014’s ‘Hercules.’

He responded, “Hate seeing this but love seeing her stand up to bullshit. Rebecca was my guardian angel sent from heaven on our set. I love that woman. I’d like to find out who did this.”

So, that’s one person down … and a handful of others left as the would-be culprit. Just goes to show — not everyone in Hollywood is all that sweet — at least according to Rebecca.