Nigel Farage says Donald Trump's inauguration will be historic because it marks a "significant change in direction" for America.
The former Ukip leader, who was the first British politician to meet Mr Trump after his election win, is attending the ceremony in Washington DC, where Mr Trump arrived on Thursday as he prepares to be sworn in as US president.
After arriving in the US capital, Mr Farage told the Press Association: "I get a sense of the history, and that this particular inauguration is a very significant one because in so many areas it marks a significant change in direction. I'm very excited about it.
"In terms of America's place in the world and its direction, what is happening tomorrow is very significant indeed.
"I'm very, very pleased that post-Brexit we got involved in this."
Mr Farage will attend a lavish party at the five-star Hay-Adams Hotel on Thursday evening to celebrate Mr Trump's inauguration.
It was reported that he will host the event with Arron Banks, the Leave campaign financer, but Mr Farage insisted he was a guest and Mr Trump is not expected to attend.
"It's to celebrate the fact that in 2016 we saw this dramatic change in politics," he said.
"I suppose the party is the international dimension in all this.
"We've had Brexit and perhaps that contributed just a little bit to things changing in the USA and who's to say that bandwagon won't continue to roll in 2017 across much of Europe."
Mr Farage is attending the inauguration ceremony on Friday as a guest of Mississippi Governor Phil Bryant, who first invited him to a Trump rally in Jackson, Mississippi in August.
Mr Trump hailed Mr Farage as a "great guy" during an interview with The Times earlier this week.
Inauguration events start on Thursday when Mr Trump and Vice President elect Mike Pence lay wreaths at the Arlington National Cemetery in Virginia.
A concert - dubbed the Make America Great Again! Welcome Celebration - will then take place at the Lincoln Memorial.
Country stars Lee Greenwood and Toby Keith and rock band 3 Doors Down will perform at the event amid reports Mr Trump has struggled to attract famous names to take part.
Broadway star Jennifer Holliday pulled out of the concert, citing concerns raised by fans from the LGBT community.