ITV News Political Reporter Jasmine Cameron-Chileshe was live from outside GB News' office in London after Boris Johnson announced his new contract with the channel
Taking up his post in the new year, he will "play a key role in the channel’s coverage of both the UK general election and the US elections next year."
Mr Johnson will also create and present a new series "showcasing the power of Britain around the world, as well as hosting the occasional special in front of live audiences around the UK."
In a video released by GB News on X, formerly Twitter, the ex-MP for Uxbridge and South Ruislip addresses viewers: "Hi folks, Boris Johnson here. I'm excited to say that I'm shortly going to be joining you on GB News.
"I'm going to be giving this remarkable, new TV channel my unvarnished views on everything - from Russia, China, the war in Ukraine, how we meet all those challenges, to the huge opportunities that lie ahead for us. Why I think our best days are yet to come.
"And why, on the whole, the people of the world want to see more global Britain - not less. So join me on GB News for some Great British television."
He quit as prime minister in 2022, following a mass revolt by ministers over his leadership.
He now joins a number of former Tory colleagues including close ally Sir Jacob Rees-Mogg and current Conservative deputy chairman Lee Anderson at the channel.
Former pensions minister Esther McVey and backbencher Philip Davies are also presenters.
The channel has been embroiled in scandal in recent months after three of its on-air employees were suspended.
Both Laurence Fox and the channel's main presenter Dan Wootton were suspended amid an internal investigation and a probe by regulator Ofcom.
The regulator received around 7,300 complaints about an episode where Fox made a series of derogatory remarks about political correspondent Ava-Santina Evans, while Wootton could be heard laughing during the segment.
A third commentator, Calvin Robinson, was also suspended.
Mr Johnson has earned millions of pounds since leaving office, mostly for speaking fees but also for his upcoming memoirs.
The decision to join GB News is a coup for the TV channel, while also giving Mr Johnson a new platform to air his views and opinions.
He has made recurring interventions since leaving office on the war in Ukraine, repeatedly urging Western leaders to go further in offering support to Kyiv in its fight against Russia.
Mr Johnson sought advice from Whitehall’s appointments watchdog before taking up the job.
The Advisory Committee on Business Appointments said it did not have any “particular concerns” about the role.
In June this year, he was also unveiled as a new columnist for the Daily Mail, a day after a report found he repeatedly lied to MPs over the Downing Street partygate scandal.
He pens a weekly item for the tabloid newspaper, with media sources suggesting the contract could be worth £1m.
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