Clare Cathcart, a British actress who had roles in Call the Midwife, New Tricks and Casualty, died on Friday at her home in Brighton.
The Fermanagh-born actress, 48, most recently appeared the BBC drama Call the Midwife playing Mrs Torpy. She also played roles in Doctors and The Bill.
"Clare was brilliant, fearless and funny; a wonderful actor who we are immensely proud to have represented", a representative for Cathcart said in a statement.
"Without her razor-sharp with and glorious laugh the world will seem a darker place. We will miss her enormously", it continued.
Her cause of death has not been confirmed.
Clare had also recently filmed for upcoming thriller The White Room, in which she plays a school teacher.
On the stage, Clare had performed at the National Theatre, Royal Court and at the RSC and at the Chichester Festival.
Stars such as Shane Richie and Miranda Hart have been paying tribute to her on Twitter.
Fellow Call the Midwife star Miranda Hart has tweeted she is "reeling" from the news of Clare's death. Clare was a "ball of joy", she says.
Miranda adds: "Had the privilege of some serious laughing with her on call the midwife."
EastEnders star Shane Richie , who plays Alfie Moon in the BBC soap, has also tweeted his fond memories of the actress: "The little time I spent with you will stay with me always, you funny, beautiful crazy lady," he wrote.