Nigel Farage has told ITV Tonight his political ally Donald Trump's inauguration should be celebrated by America and Britain and predicted the 45th US president will be judged a success if he can generate new jobs.
The swearing-in ceremony in Washington DC comes amid anti-Trump protests in cities across America.
But Farage has backed the billionaire tycoon-turned-politician to stand up for the rights of 319 million people in the White House.
"I genuinely believe he's going to be the champion of ordinary American people," he said.
The former Ukip leader, who befriended Trump after endorsing him at a campaign rally, hosted an inauguration party in Washington on the eve of the event.
At least 500 people were invited to the celebration at a hotel close to the White House.
Speaking in the city, Farage endorsed the new president during his appearance on ITV Tonight's President Trump: America's Greatest Gamble?
He said Trump will have to raise employment levels in deprived areas to be judged a success as Barack Obama's successor.
"I think the absolute key test for him is to bring jobs back into those areas," the MEP said.
Farage suggested there are already indications firms want to do business with the former hotel mogul.
"I'll tell you what's fascinating," he said.
"Even before he's become president there are companies announcing another 700 jobs here, a factory saved there."
Farage said British business stands to directly benefit from the Trump presidency post-Brexit after Obama famously predicted a vote to leave the EU would see the UK's trade status plummet.
"There's no more back of the queue for Britain," Farage said. "In fact I think we've got an opportunity to be at the front of the queue. And I think that'll be a very good thing for trade, jobs and investment for both countries."
Farage became the first senior UK politician to meet the US president-elect following his shock election win in November.
Farage later claimed the Government had banned Cabinet ministers from speaking to him after he offered to use his position of influence with Trump to become a "bridge" between the White House and Downing Street.
The Government denied the claim and said it had "no vacancy" for a go-between.
- President Trump: America's Greatest Gamble? Watch on the ITV Hub