Holby City star Tina Hobley is leaving the long-running medical drama after 12 years as ward sister Chrissie Williams.
The actress said she was looking forward to "new challenges" after she leaves her role as the unlucky-in-love nurse later this year.
Over the years BBC1 viewers have seen her held hostage by consultant Stuart McElroy, falling for a doctor she later found to be gay and getting pregnant in a one-night-stand.
She said of her departure: "Being a part of the Holby family for the last 12 years has been an experience I will treasure forever but it's time to explore some new challenges.
"I have loved playing Chrissie Williams but I'm also looking forward to getting my teeth in to some other characters and new roles."
Executive producer Oliver Kent said: "As Chrissie Williams, Tina Hobley has been a leading light at Holby City for over a decade and we will be very sorry to see her go.
"It has been a joy and privilege to work with her and she has been massively popular with the audience. We wish her all the very best for the future."
She is expected to continue on screen until November.