Tributes are pouring in for Coronation Street actress Anne Kirkbride, who has died aged 60 after a short illness.
A statement on the soap's website said the cast and crew are "heartbroken".
The actress was part of the ITV soap for 44 years after joining in 1972 - and has been part of some major storylines.
In a statement William Roache, who played Anne's onscreen husband Ken Barlow, said: "I feel Anne's loss so personally having worked closely with her for over 40 years."
"She was such a loving and vibrant person. You always knew she was there because her laugh was never far away."
Here is what happened in 1983 when he found out about her character's affair with Mike Baldwin.
Watch her first appearance on the cobbles back in 1972:
Kirkbride's on-screen daughter Kate Ford wrote: "Heartbroken at the loss of my friend and beautiful on screen mummy. The most crazy funny 100 per cent human. My life was enriched by her".
Les Dennis, who plays Michael Rodwell, tweeted: "So very sad to hear our lovely Anne Kirkbride has died. One of the true icons of @itvcorrie. We will all miss you. The nations favourite."
Alan Halsall, who has played Tyrone in the soap since 1998, said: "Rip Annie beautiful woman inside & out xxx #devastated #corriefamily".
"My beautiful darling friend, Anne Kirkbride, passed away in a room filled with love. God Bless, my Darling Girl! Peace and rest," said Beverley Callard, who plays Liz McDonald.
Actress and singer Kym Marsh, who plays Michelle Connor, tweeted: "Cannot describe how devastated we all are. Sleep tight gorgeous lady we will miss you ridiculous amounts RIP Annie x".
Gaynor Faye, who starred alongside Kirkbride from 1995 to 1999, wrote: "Anne Kirkbride's smile & laugh always lit up the #Corrie green room...may it light up the sky as bright!"
Actor and singer Adam Rickitt, who was also in the show in the late 90s, wrote: "Just heard..so gutted. Annie..u were pure class..a smile always when needed and a hug always from the heart".
Other famous names from UK television have also expressed their condolences, including presenter Lorraine Kelly who wrote: "So very sad to hear of death of Anne Kirkbride - Thoughts with her husband and family and everyone who loved her. Corrie legend."
Adam Woodyatt, who plays Ian Beale in EastEnders, tweeted: "Such sad news about Anne Kirkbride. My thoughts are with her family and all the Corrie cast and crew."
Presenter and actor Paddy McGuinness posted a picture of a pair of glasses, similar to those worn by Deirdre in the soap.
"Anne Kirkbride RIP. A part of our lives whether you knew her or not. She created such an iconic character," he wrote.
Phillip Schofield tweeted: "Just checked my phone and have heard of the sad loss of the wonderful Anne Kirkbride. My deepest condolences to the #Corrie family x."
News of Kirkbride's death has featured on many of Tuesday's newspaper front pages.
One of the most memorable plots - the love triangle between Deirdre, Ken and Mike Baldwin - led to her being voted TV Personality Of The Year in 1983.
When her character chose Ken Barlow over Mike Baldwin in 1983, cheers went up as the "result" flashed up on the Old Trafford scoreboard.
It read: "Ken and Deirdre reunited. Ken 1 - Mike 0."
In 1993 it was revealed she had throat cancer and she took three months off the show while undergoing treatment. Many major storylines led viewers and fans to act as if Deirdre was a real person.
So much so that in 1998, British Prime Minister Tony Blair promised to intervene to get Deirdre released from prison after she was duped into mortgage fraud.
Mr Blair gave his full support to the "Free The Weatherfield One" campaign.
The show's executive producer, Kieran Roberts, said the cast felt "blessed" to have worked with her. He added: "There are no words to describe the sense of grief we feel at Anne's passing."
ITV's Director of Television, Peter Fincham, said Kirkbride had created a "unique and unforgettable character".
In September Kirkbride was granted an extended break from the soap by producers. She was expected to be absent from the show for three months.
Kirkbride is survived by her husband, David, and her brother John.
This was her last scene on the soap, which aired last year: