Kirsty Gallacher has stepped back from GB News to focus on her health after discovering a tumour in her ear.
The 45-year-old, who quit Sky News to join the channel when it launched in the summer, has said that while the tumour is benign, it has caused her severe tinnitus.
She also explained that the "sleep deprivation" from the 3am starts at GB News have exacerbated her symptoms.
However, Kirsty hailed GB News as being "incredibly supportive" and said that she hoped to return to the channel when she is able to do so.
Taking to Instagram, she wrote: "During the summer I discovered I have a tumour in the inner canal of my right ear. Thankfully, it's benign and not hugely detrimental to my normal life.
"However, the tumour has caused severe tinnitis which makes it difficult to sleep. Sadly my 3am starts at GB News, compounded by sleep deprivation, are exacerbating my symptoms.
"I've taken the difficult decision to step back from my role on the Great British Breakfast while I focus on my health. GB News has been incredibly supportive of me and I look forward to returning to the channel as soon as I can.
"As I adjust to managing my condition, I will carry on my less disruptive work commitments and continue maintaining a healthy lifestyle and training so I can get back to my normal routine quickly."
Fans and friends flocked to comment and wish her well, with co-star Mercy Muroki writing: "Wish you all the best as you recover, Kirsty. See you soon."
While former GMB director Erron Gordon wrote: "Wishing you the very best Kirsty. Those early starts are tough. Take it easy."
GB News' own social media page also commented, writing: "Wishing you all the best @TheRealKirstyG and good luck with your recovery, from all your friends at GB News."
Kirsty announced that she was joining GB News back in March alongside former BBC News presenter Simon McCoy.
A statement from GB News said at the time: "Popular broadcaster Kirsty Gallacher is joining GB News as part of the new channel's breakfast team.
"Kirsty was one of the main faces of Sky Sports and Sky Sports News for almost 20 years and has anchored various news programmes including Channel 4's morning show RI:SE.
"Her versatility as a host has extended to dozens of other shows including Ant Versus Dec on Saturday Night Takeaway, Gladiators, Kirsty's Home Videos, Simply the Best and the reality series The Games.
"She appeared for charity on Who Wants to Be a Millionaire and took part in the 2015 series of Strictly Come Dancing. She has also released workout DVDs such as Body Sculpt with Kirsty Gallacher and guest presented Lorraine on ITV Breakfast.”
