Daytime television presenter Trisha Goddard is moving to Five after six years with ITV.
Goddard said she would also work on prime-time projects
Goddard will present a morning weekday programme on the channel after striking a two-year deal, due to start in 2005.
Her daily chat show, Trisha, has proved a huge hit and regularly pulls in 1.6 million viewers.
Kim Peat, Five's controller of daytime television, said: "It's tremendously exciting to have Trisha as part of our daytime schedule."
Goddard said the deal would also allow her to work on a number prime-time projects.
She said: "I've had six fantastic years at ITV and been fortunate enough to work with some great people.
"However, emotional upheaval can make one re-evaluate one's life, and I know in my heart that it's time for a change.
"I feel the need to refresh and reinvigorate my television career and I've been really impressed by the energy and enthusiasm evident in Five's approach."
The 46-year-old, whose mother and personal trainer both died this year, added: "Personally and emotionally 2004 has been one of the most difficult years of my life.
"I've struggled with some devastating losses which are still painful."
Before joining ITV in 1998, she worked in Australia for 13 years as a TV reporter, presenter and
government adviser on mental health.
Her new show on Five will follow a similar format to her current programme.
It will be made by Town House Productions, a new independent company co-owned by Goddard and Malcolm Allsop, former director of programmes at Anglia Television.
It was Allsop who recruited Goddard after original host Vanessa Feltz was dropped in 1998 following a row over her wages.
Diane Nelmes of production company Granada said: "I would like to thank Trisha for her contribution to ITV over the last six years."
Five's director of programmes, Dan Chambers, said: "I'm delighted we've persuaded one of the biggest stars of British television to join Five.
"It's a sign of the strides the channel has made that we have been able to convince someone of Trisha's calibre that Five will be a great home for her."