Evan Davis, the BBC's economics editor and host of BBC Two business programme Dragon's Den, is to become a presenter on Radio 4's Today programme.
Davis guest presented Today for two weeks over the summer
Davis will present the flagship current affairs show in rotation with regular hosts John Humphrys, Sarah Montague, James Naughtie and Edward Stourton.
"Today is a radio institution and I'd obviously be mad to turn down a chance to present it," said the 45-year-old.
Part-time host Carolyn Quinn is leaving the show to focus on other projects.
The changes to the Today line-up will take place in the spring.
"Evan is simply one of the outstanding BBC journalists of his generation," said Today editor Ceri Thomas.
"He's knowledgeable, surprising and brilliantly clear-sighted when it comes to working out what really matters on the big stories."
Davis, who will join the Today team full-time for a year, was appointed the BBC's economics editor in 2001.
He joined the BBC in 1993 after working as an economist for the Institute for Fiscal Studies and the London Business School's Centre for Business Strategy.