Protesters have successfully inflated the 'Donald Trump Baby' blimp in Parliament Square Garden, as mass protests are set to take place across the capital.
The six-metre balloon was lifted in the air to cheers from a crowd on Friday morning (local time), but it remains to be seen how long it will last.
Trump Baby Blimp Organiser Leo Murray told Newshub: "He's uniquely vulnerable to personal insults, so we've just got right down on his level to speak to him in the language he understands."
The protest group received permission from London Mayor Sadiq Khan to use the square as the grounding point for the balloon.
The US President arrived in London on Thursday afternoon following a NATO leadership summit in Brussels, and protesters were already out in force.
On Friday Mr Trump and UK Prime Minister Theresa May will meet at her country retreat in Chequers, and he will also meet the Queen at Windsor Castle.
He will almost entirely avoid ground travel, instead opting to use his presidential helicopter.
There are two major protest groups holding marches on Friday, The Women's March on London - Bring The Noise and Together Against Trump.
Metropolitan Police are reminding central Londoners that the threat to the United Kingdom of international terrorism is 'severe', an attack is highly likely and crowded places are an attractive target.