Donald Trump says Prime Minister Keir Starmer "has been very nice" and claimed a deal "can be worked out" to avoid UK tariffs.
The US president's comments came as he vowed tariffs would "definitely happen" with regard to the EU.
The world economy is bracing for the impact of Trump's imposition of the extra taxes on exports to the US, with Asian markets already tumbling after the president slapped tariffs on Canada, Mexico and China.
Canada and Mexico have vowed to retaliate with their own tariffs, and China has threatened "corresponding countermeasures".
But while the EU is set to be next on Trump's tariff hitlist, it is hoped the UK will avoid a similar fate.
Asked by the BBC about the potential for a tariff on the UK, Trump said: "It might happen with that, but it will definitely happen with the European Union. I can tell you that, because they've really taken advantage of I said, you know, we have over $300billion deficit.
"They don't take our cars, they don't take our farm products. They take almost nothing, and we take everything from the millions of cars, tremendous amounts of food and farm products. So the UK is way out of line, and we'll see the UK, but European Union is really out of line.
"UK is out of line. But I'm sure that one, I think that one, can be worked out, Prime Minister Starmer has been very nice. We've had a couple of meetings, we've had numerous phone calls, we're getting along very well, and we'll see whether or not we can balance out our budget with the European Union.
"It's $350billion deficit, so obviously, something's going to take place there."
Trump would not be drawn on a specific timeline for EU tariffs but warned "it's going to be pretty soon".