Nigel Farage arrives onstage in Jackson,Mississippi.Credit:AP
"In fact,I wouldn't vote for Hillary Clinton if she paid me,"he added.
He urged Mr Trump's supporters to get out and vote"against the establishment",and spoke of Britain's decision to leave the European Union as a positive example.
"They told us that our economy would fall off a cliff ... and David Cameron - then our prime minister,but no longer - told us we might even get World War Three,"Mr Farage said."We saw the polling industry do everything they could to demoralise our campaign. On the day of the election itself,they put us 10 points behind. But actually,they were all wrong."
Introducing Mr Farage,Mr Trump likened Brexit to the upcoming presidential vote in the US.