The news was shared in a message posted on the daytime show's Facebook page, and by Ruth Langsford and Rylan Clark, during Friday morning's episode.
The statement reads: “Some news about one of our own that has all of us at 'This Morning' in a state of shock.
“After almost thirty years of providing comfort to millions of 'This Morning' viewers, agony aunt Denise Robertson is in need of a lot of love herself today. Denise has told us she has pancreatic cancer.”
It also includes words from Denise, who says: “I'm sorry I've not been around for a couple of weeks but a persistent health issue has turned into something quite a lot bigger. I've been diagnosed with pancreatic cancer.
“It has come as a surprise to me and my family but we know many others have suffered and dealt with this condition and I don't plan to give up without a fight.
“My doctor is referring me for chemotherapy and hopefully that will start soon. I'd like to thank all the lovely viewers of 'This Morning' who have been concerned about my health and I hope I'll be back on the sofa soon.”
Denise began appearing on ‘This Morning’ in 1988, and she’s also made guest appearances on shows including ‘Loose Women’ and ‘The Paul O’Grady Show’.
Many fans have already shared good wishes with Denise, which ITV are encouraging viewers to do via their Facebook post, which can be seen below: