Victory for far-right leader Marine Le Pen in France's presidential contest would be a "questionable thing", Nigel Farage has said.
The interim Ukip leader said he had "never said a bad word" about Ms Le Pen, but he had "great difficulty" with her Front National party.
His comments came after Ms Le Pen said there was not a "hair's breadth" between her party and Mr Farage's on issues including the European Union and immigration.
The surge in support for populist parties and candidates from outside the political mainstream had made 2016 "the year of political revolution", Mr Farage said.
"First Brexit, now the Trump victory and who knows what might happen next year across the rest of Europe," he told ITV's Good Morning Britain.
Ms Le Pen hopes the same wave of anti-establishment politics will help her to victory in 2017's French presidential race.
But Mr Farage said: "That would be a questionable thing."
He added: "She is opposed to the European Union, she wants France to be an independent country, I support that.
"There are elements of her party that I have great difficulty with and I always have had."
At the weekend Ms Le Pen said it was "ridiculous" for Ukip to distance itself from the Front National.
But Mr Farage said: "I have never said a bad word about her, but I have never said a good word about her party."
On BBC's Andrew Marr Show on Sunday Ms Le Pen said: "Objectively ... on the topic of immigration and the European Union, there is not a hair's breadth of difference between what Ukip thinks and what the National Front thinks, let's be truthful here.
"Maybe Ukip is trying to counter the demonisation they are victim of by saying 'we are the good guys and the National Front are the bad guys', they can do so, but I don't feel obliged to follow this strategy, because, frankly, I feel it's a little bit ridiculous. "