US President Donald Trump said Brexit was "getting straightened out" after declaring Britain's execution had been "sloppy".
It comes as he is set to make his second state visit to the UK in September, with the US President saying "I really like the Prime Minister a lot".
"Even though he's a liberal," Trump added.
When asked whether Britain had implemented its withdrawal from the European Union successfully, he told the BBC "no, I think it has been on the sloppy side".
"But it is getting straightened out," Trump added.
He said Starmer "did a good trade deal with us, which a lot of countries have not been able to do".
Despite successive Conservative Prime Ministers, including Boris Johnson, Theresa May, Liz Truss and Rishi Sunak playing key roles in the implementation of the referendum result, Trump's assessment of Brexit's success aligns more with recent polling.
It also comes as his biggest ally in the UK, Nigel Farage, said "Brexit (had) failed" and Britain had not seen an economic benefit.
REUTERS
|Donald Trump and Melania Trump will be hosted at Windsor Castle
British voters' support for Brexit is at an all time low, which found 56 per cent of those polled by YouGov wanted the UK to return to being part of the EU.
It also found 61 per cent believed Brexit had been a failure.
Trump will be welcomed to the UK by King Charles from September 17 to 19 on an unprecedented second state visit as he will be hosted at Windsor Castle.
He will also meet with Starmer.
PA | Sir Keir Starmer was praised by Trump for 'straightening out' Brexit
Unlike French President Emmanuel Macron, who was afforded the opportunity to address MPs and peers last week, Trump will not get that chance.
"I think let them go and have a good time," Trump said when asked about not being given the opportunity.
On his upcoming visit, the US President said he wanted to "have a good time and respect King Charles, because he is a great gentleman".
Trump was also questioned about his increasingly tense relationship with Russian President Vladimir Putin amid the war in Ukraine.
Trump highlighted he was running out of patience with Putin.
However, when speaking in the Oval Office on Monday, he said he wasn't "done" with him despite frustrations over a peace deal stalling.
He was joined by Nato secretary general Mark Rutte, with the US President saying he was "very unhappy" with Russia.
Trump promised to impose "very severe tariffs" on the country "if we don't have a deal in 50 days".
"I'm disappointed in President Putin, because I thought we would have had a deal two months ago," he said.
"But it doesn't seem to get there."
Trump said it was "very simple" that if the deal isn't achieved in 50 days, the tariffs will be introduced "100 per cent".
"It's just the way it is. I hope we don't have to do it," he said.