Sammy Winward, 29, has played stable manager Katie Addyman in in Emmerdale since July 2001 - when she was aged just 15.
EMMERDALE'S ADELE SILVA REVEALS PREGNANCY JOY FOLLOWING STRING OF MISCARRIAGES
Speaking to The Sun, a source said: "Sammy is the Michelle Keegan of Emmerdale so everyone is gutted that she's leaving.
"She's hugely popular and her character has been a big part in the show overtaking EastEnders."
The 29-year-old - who was voted one of FHM's 100 Sexiest Women - will leave the soap next year to focus on other acting opportunities, but it is claimed she would not like her character to be killed off.
The source added: "The producers haven't decided yet. Emmerdale love a big death because it's great for their ratings."
EMMERDALE'S ROXIE SHAHIDI: 'MY HUSBAND PROPOSED BEFORE WE'D EVEN KISSED'
Katie Addyman was first introduced to viewers 13 years ago as Andy Sugden's first girlfriend, and has been at the centre of many explosive plots since.
Explosive plots like, say, the moment she fell down an old mine shaft and shattered her pelvis...
And her departure, announced shortly after she shot the soap's Christmas episodes, which will see her character re-marry Andy, played by Kelvin Fletcher, is sure to be just as dramatic.
A source added: “Sammy is leaving early next year.”
Will you be sad to see Sammy leave the dales? Let us know via the comments box below now.