Donald Trump joked that King Charles was able to accomplish something he's 'never been able to do' after Congressional Democrats gave the King a standing ovation.

Charles spoke to Congress for about 20 minutes on Tuesday afternoon to mark the 250th anniversary of American independence from Britain with gratitude that the two countries united to build 'one of the most consequential alliances in human history.'

At a state dinner held hours later, Trump welcomed Charles and Queen Camilla by praising the speech and joking that the king got the Democrats to applaud in a way they refuse to for him.

'I also want to, before we really begin, congratulate Charles on having made a fantastic speech today at Congress. He got the Democrats to stand, I've never been able to do that,' Trump said.

'I can't believe it! They liked him more than they've ever liked any Republican... or Democrat, actually!'

However, Trump returned to praising the King for his address, that emphasized the special relationship between the two countries.  

'I just want to thank you and congratulations, it's not an easy thing to do. That's a tough place.' 

While speaking to a joint session of Congress, Charles highlighted the historical and cultural ties that have cemented an enduring bond between the United States and the United Kingdom. 

In doing so he became only the second British monarch in history to address Congress, following in the footsteps of his late mother Elizabeth II.

The King received a four-minute standing ovation as he walked into the chamber before he had even said a word, and another loud round of applause as he took to his feet to speak.

His 20-minute speech was greeted with further rounds of applause and laughter from US lawmakers. 

But even as he spoke in unifying, optimistic terms, he delivered a series of nuanced warnings encouraging leaders in the US to remain collaborative and engaged in global affairs.

He said the alliance between the US and the UK, tested anew by President Donald Trump's war in Iran, 'cannot rest on past achievements.' 

Charles urged 'unyielding resolve' in backing Ukraine against Russia and heralded the NATO alliance that Trump has consistently undermined. 

The king praised religious pluralism and interfaith dialogue in terms that are rare in Trump's Washington. 

As the White House rolls back regulations aimed at denting climate change, the king encouraged those in power to 'reflect on our shared responsibility to safeguard nature, our most precious and irreplaceable asset.'

At one point, Charles traced the notion of checks and balances on executive power to the Magna Carta, the foundational legal document sealed by King John in 1215. 

Trump told The New York Times earlier this year that he was constrained only by 'my own morality.'

And acknowledging a scandal that has roiled politics in both the US and UK, Charles subtly alluded to the victims of Jeffrey Epstein, the convicted sex offender with ties to British officials, including the king's brother, Andrew.

Charles is on a four-day visit to the US intended to both celebrate American independence and to repair the country's fraying relationship with the UK. 

He hardly arrived in Washington as an oppositional figure to Trump. Joined by Queen Camilla, Charles had a warm greeting with the president and first lady Melania Trump at the White House earlier Tuesday.

In his welcome remarks, Trump also highlighted the shared history between the two countries.

'American patriots today can sing, 'My country, 'tis of thee, sweet land of liberty,' only because our colonial ancestors first sang, 'God save the king,' Trump said.

The leaders met privately in the Oval Office for a meeting Trump later described as 'really good,' adding that Charles is a 'fantastic person.'

Trump hosted the royal couple for a jovial state dinner later Tuesday in the East Room of the White House. 

About 130 guests were seated at two long tables that were decorated with low floral arrangements. 

The guests included tech leaders such as outgoing Apple CEO Tim Cook and Amazon founder Jeff Bezos, along with conservative Supreme Court justices and several Fox News journalists and hosts.

Charles and Camilla will continue their US tour this week with stops in New York City and Virginia.

While the king paid tribute to his mother's 1991 remarks to Congress, he acknowledged that today's environment is 'more volatile and more dangerous than the world to which my late mother spoke.'

Many of the lawmakers in the room were at Saturday's White House Correspondents' Dinner, which was disrupted by a shooting that authorities have described as an attempted assassination against Trump.

'Let me say with unshakeable resolve,' Charles said. 'Such acts of violence will never succeed.'

Meanwhile, Trump's up-and-down relationship with British Prime Minister Keir Starmer has taken a particularly sour turn over the past several months as the Republican president has sought to rally international support for the war in Iran. 

Trump criticized Starmer, who has largely resisted his overtures, by saying, 'This is not Winston Churchill that we're dealing with.'

Trump has also imposed tariffs on the U.K. and warned of additional levies despite a Supreme Court ruling earlier this year that has made such unilateral moves more challenging. 

The President threatened just last week to slap a 'big tariff' on the UK if it doesn't scrap a digital services tax on US technology companies.