Kai Trump reveals what 'red button' in Donald Trump's Oval Office does while attending UFC White House

Kai Trump has revealed what the 'red button' in The Oval Office - which is controlled by her grandfather and US President Donald Trump - actually does.

The 19-year-old, who made her LPGA Tour golf debut last year as a wildcard, attended the UFC Freedom 250 card staged earlier this month.

She posted a video of her experience during the event, which was staged at the White House, to her YouTube channel, which has over 1.5 million subscribers.

In the video, titled 'Front row at the UFC White House Fight', Trump filmed footage of herself watching the Freedom 250 main event between Justin Gaethje and defending lightweight champion Ilia Topuria, which Gaethje won.

The card was held on the South Lawn of the White House as part of USA's 250th anniversary of independence celebrations, with President Trump in attendance at the event.

As part of her video, Trump gained exclusive access to the Oval Office, which is where her grandfather and President conducts a significant amount of his government business.

It is where he met Barcelona and Argentina legend Lionel Messi, and the rest of the Inter Miami squad, during last summer's Club World Cup.

The visit garnered controversy, as President Trump spoke to reporters about the war with Iran - while the squad was stood behind him.

The then Inter Miami coach Javier Mascherano claimed he was told that 'only football' would be discussed during the visit.

This time around, Trump's granddaughter had the Oval Office all to herself - apart from the usual members of security - and gave a guided tour of the room.

She focused in on a bright red button that is situated on the President's desk, placed on top of a small wooden box.

According to US outlet People, Trump has been known to jokingly move the box away from first-time guests at the White House, telling them: "Don't worry about that. No-one wants me to push that button, so we'll just keep it over here. Now, what were you saying?"

But rather than the button having any sort of national importance, it is instead pressed by Trump whenever he wants a fresh Diet Coke brought directly to his desk by a butler.

"Everything's gold, because my grandpa hates gold... that's a joke, he loves gold. It's his favourite thing on the planet," his granddaughter said, while showing viewers around the Oval Office.

"This is his desk. We've got some Sharpies, because he loves his Sharpies. This is a gold Sharpie, some gold coasters, and his chair.

"And then he has a Diet Coke button. So he presses the red button, and Diet Coke comes out.

"That's the Oval Office. This is stuff that's been around forever, so it's really special. This chair is pretty comfortable, too. It's a heavy, big chair, but it's nice."