Penny Smith is quitting GMTV after 17 years on the sofa, the show has confirmed.
The 51-year-old's departure comes amid plans for a revamp for the breakfast news show and follows weeks of speculation over the future of GMTV's presenters as commercial broadcaster ITV faces tough economic challenges.
Smith's co-host John Stapleton has been appointed the show's first special correspondent.
His new role will see him go on the road to "bring viewers his inimitable eye-witness accounts of the major national and international stories".
Smith will host a new BBC Radio 2 opera show in June and is working on her third novel. She is also said to be in talks with ITV about other projects.
She said: "It's an ideal time for me to say goodbye to early mornings. Now that the format has changed, I have taken the plunge and am moving on."
GMTV's managing editor Neil Thompson said: "Penny has been a welcoming and familiar face on Britain's breakfast screens for many years.
"She has become a hallmark of GMTV's presentation, not only on the sofa but also as a newsreader. She has done a fantastic job over the last 17 years and has made an enormous contribution to the success of the News Hour."
Veteran broadcaster Stapleton is returning to his roots after cutting his teeth as a reporter-at-large for topical news show Nationwide.
He said: "I'm going back to doing what I love best - covering major national and international news stories, and, after 12 years of getting up at 3.45am, I'm looking forward to having at least a few lie-ins a week when I'm not on duty."