Eleanor Tomlinson has called for her pay to match that of her Poldark co-star Aidan Turner.
The actress agreed that while Turner was a bigger name at the start of the BBC series, they are now both its leads and should pocket the same salary.
Mammoth Screen, who produce the popular show, defended paying Turner more as he has received "significantly more screen time than any other character" throughout its series.
Asked whether she thought she was paid the same as Turner, Tomlinson told Red Magazine: "My guess is no.
"And while at the beginning that might have been OK, he was a bigger star than me, now I don't think so.
"We're equal leads of the show, so I'd be pretty upset if the gap hadn't closed."
A spokeswoman for Mammoth Screen confirmed Tomlinson's suspicions in a statement.
"Whilst we can't and won't disclose the details, we do pay Aidan Turner more for playing Ross Poldark as throughout all series Ross has significantly more screen time than any other character," she said.
Tomlinson, 26, said she and Turner are great friends "although we do row".
"(We row about) everything - usually our characters," she said.
"We're both ridiculously protective of them and squabble like an old married couple.
"Usually it's one of us saying that our character wouldn't behave a certain way. Aidan loves everything being his (character's). But then he loves to wind me up."
The actor has become a heartthrob following his turn in the series and his shirtless scenes usually trigger hundreds of comments on social media.
Tomlinson said: "It was all people could talk about.
"And when you make eight hours of television and people can only remember two scenes, you're like, 'Oh come on'. (But) I get it.
"Like, don't get me wrong. I'm looking, going, 'Sure, yeah. I'm with you ladies'.
"But I can see why he got frustrated with it."
Tomlinson initially tried out to play Elizabeth, the role that went to Heida Reed.
"They told me they couldn't see me as a Demelza at all, they wouldn't even let me audition," she said.
"So, it was quite a shock when they eventually offered me the role."
The full interview appears in the July issue of Red, on sale on May 30.