ITV News health and science editor Emily Morgan has died at the age of 45 after a short battle with lung cancer, the broadcaster said.
Ms Morgan worked as a journalist at ITV News for 23 years, and a colleague described her as a “true trailblazer”.
ITN announced her death on Twitter and said it is “devastated”.
“Emily was a hugely talented journalist and a much-loved friend and mentor to so many here,” ITN continued.
“She will be greatly missed. Our thoughts are with Emily’s family.”
Others also took to Twitter to pay tribute to Ms Morgan, including Health Secretary Steve Barclay and many of her colleagues.
The politician tweeted: “Her exemplary reporting throughout the Covid pandemic was a vital public service – helping to keep people safe.”
Andrew Dagnell, editor at ITV Network News, said: “We are deeply saddened by the passing of our remarkable colleague, Emily Morgan.
“Emily was not only an incredibly talented journalist, but a much-loved member of the ITV Newsroom and her absence will be deeply felt by all who knew her.”
He said Ms Morgan played a “pivotal role” in shaping ITV coverage through some of the “most important stories of our time”.
He referenced her “courageous” reporting through the Covid-19 pandemic, during which she visited hospitals and healthcare workers on the the front lines to share their stories.
“Her reporting was instrumental in exposing the immense pressure and strain that NHS workers were under, and she became a trusted voice for the public during an unprecedented time,” Mr Dagnell said.
“Emily’s passion for the role was evident in everything she did and her work was a constant reminder of why journalism matters.
“Her dedication to informing and educating our viewers will continue to inspire all those who were privileged to work alongside her.”
He said Ms Morgan was “proud” to be a journalist but even more proud of her family, whom she “adored”.
“We are sending them our love and support at this unthinkably difficult time,” Mr Dagnell added.
“Emily was an exceptional journalist, a devoted mother and wife and a true trailblazer in our field.
“Her friendship, her professionalism and her enormous contribution to our industry and to the public conversation will not be forgotten.”
ITV News presenter Julie Etchingham called Ms Morgan a “fearless journalist”.
“The most brilliant, beautiful woman inside and out,” she tweeted.
“A devoted Mum. A wonderful, fearless journalist and a dear colleague who lived her life with radiating joy and to the full.
“Thinking of all her family especially and all those closest to her.”
Chris Ship, royal editor for ITV News, said his colleague and friend had been “full of humanity”.
“She was such a beautiful person and a dear friend,” he said.
“As Health Editor, Emily was fearless in reporting Covid to the nation in 2020.
“Talented, kind, full of humanity. She was 45.”
BBC Breakfast editor Richard Frediani, who used to work for ITV News, called her a “first class journalist”.
He tweeted: “Brilliant. Talented. Intelligent. Dedicated. Fearless.
“Emily Morgan will always remain in the hearts of all those lucky enough to have worked with her.
“A first class journalist who will be missed by her family and many friends.”