Cathcart worked extensively on stage and was best know for TV’s ”Call the Midwife”
Actress Clare Cathcart has died aged 48 at her home in Brighton.
"It is with huge sadness that we have to report the death of our beloved friend and client Clare Cathcart," a representative of her agent said in a statement.
"Clare was brilliant, fearless and funny; a wonderful actor who we are immensely proud to have represented."
Cathcart worked for numerous theatres including The Royal Court, RSC and National. Her notable credits included Our Private Life at the Court, The Comedy of Errors at the National, and Kathy Burke's revival of Once A Catholic at the Tricycle Theatre.
She became a familiar face through her TV work in New Tricks and Call The Midwife.
Call The Midwife's Miranda Hart was among many to pay tribute on Twitter. She wrote: "Reeling from closer to home news of Clare Cathcart. Had the privilege of some serious laughing with her on Call the Midwife. A ball of joy."
The cause of her death has not been confirmed.
Her representative added: "Without her razor-sharp wit and glorious laugh the world will seem a darker place. We will miss her enormously."