Journalist, broadcaster, and political strategist Guto Harri will join GB News to co-host a weekly news and discussion programme after the channel launches on June 13.
Harri was communications chief to Boris Johnson when he was Mayor of London— helping to build the future UK Prime Minister's brand in the lead-up to the 2012 London Olympics.
Harri will continue to host S4C's current affairs television programme Y Byd yn ei Le.
He graduated from Oxford University as a journalist and spent 18 years working for the BBC, where his positions included chief political correspondent, Rome Correspondent, and North America Business correspondent.
He has written for UK newspapers including The Times, Telegraph, and GQ magazine, where he is contributing political editor.
Additionally, he is a regular commentator on programmes for LBC, Sky, CNN, Newsnight, and BBC radio.
Harri said: "GB News is pioneering a new way in television news and debate with an energy and feistiness that really appeals to me.
"Most importantly the channel is determined to reflect as well as respect the range of views of its audience across the UK."