BBC's economics editor Robert Peston has said joining rival channel ITV has been the "hardest career decision" of his life.
The journalist and presenter will take up the role of political editor on ITV News, and will also a host a new show, Peston On Sunday.
The 55-year-old reporter, whose departure marks the end of a ten-year stint at the public service broadcaster, takes over from Tom Bradby, the new presenter of ITV News At Ten.
Peston said: "I am very excited by ITV's plans to create a distinctive and authoritative new voice in news and political coverage. Leaving the wonderful BBC has been the hardest career decision of my life, but it's impossible to turn down an opportunity like this."
Geoff Hill, editor of ITV News, said: "I'm delighted that Robert is joining us at such an important time as we continue to develop News At Ten. He is a hugely respected and competitive journalist, renowned for agenda-setting journalism.
"Our news programmes will benefit greatly from his distinctive style and his political expertise, and his appointment sends out a clear message about our ambitions."