Appearing on LBC Radio with host Nigel Farage, the leader of the Brexit Party, the US president also heaped praise on Prime Minister Boris Johnson as a fantastic guy.
Mr Trump said: I have great relationships with many of the leaders, including Boris who’s a fantastic man – I think he’s the exact right guy for the times.
Turning to the Labour leader, he added: Corbyn would be so bad for your country, he’d be so bad, he’d take you in such a bad way.
He’d take you into such bad places. But your country has tremendous potential, it’s a great country.
The prime minister has repeatedly dismissed speculation of an electoral pact with the Brexit Party ahead of the 12 December poll, despite an offer from Mr Farage.
Yet, Mr Farage has refused to rule out the prospect of the Brexit Party withdrawing candidates from hundreds of seats in order to instead target a small number of Labour-held constituencies.
This would likely prove a huge boost to Mr Johnson’s chances of leading the Tories to victory. And Mr Trump speculated the two men would end up doing something as he phoned in to Mr Farage’s radio show.
I know that you and him will end up doing something that could be terrific if you and he get together it’s [an] unstoppable force, he said.