Cathy Shipton says "Casualty" bosses made her change her accent on the show.
The 62-year-old actress - who is best known for portraying Lisa "Duffy" Duffin on the BBC medical drama - says the producers made her alter her character's West Country twang she made her debut with on the ward back in 1986.
Cathy appeared on "This Morning" on Thursday (28.03.19) and was played a clip of an old episode where Duffy had a different voice, and explained: "This is my first telly, I have never done telly.
"I've done tiny little bits but you blink and miss me.
"Suddenly, you're a Saturday night jewel in the ground on TV...
"One of the most inexperienced actors and they ask her to do an accent!"
Phillip Schofield then commented: "It's not the accent, it's just it disappeared!"
To which Cathy replied: "Well yes, because we got a new producer and he said, "Well Duffy's been listening to lots of Radio 4".
"I went, "OK", because it meant I could be like this!"
The 62-year-old soap actress - who is from Lewisham in London - also said the dementia storyline that her character is undergoing is the "toughest" she has ever done.
She said: "It's undoubtedly the toughest.
"It's a bittersweet storyline in a way as a performer because obviously this show is responsible, everything is based on fact that we put on screen for a guest character or a regular.
"And people are going through a lot of the issues we show in their lives.
"They've taken a lot of care. They've consulted Dementia UK so they played it up very slowly.
"I think the writing has been so careful."