Activists inflate a giant balloon depicting US President Donald Trump as an orange baby in north London on July 10, 2018 ahead of a demonstration in London to coincide with the visit of the US president.
Although he will visit the United States ambassador's residence, he is largely avoiding central London, where the largest protests are expected Friday.
Mrs May will be looking to improve her often publicly strained relationship with the USA president as she pushes for a post-Brexit trade deal with America.
The US president gave a brief wave to the crowd before descending the steps holding the hand of the First Lady, who wore a fitted beige dress and red belt.
Protestors said they will still transport the balloon to Scotland overnight, and will fly it elsewhere on Saturday. "But maybe they're taking a little bit of a different route, so I don't know if that's what they voted for", said Trump.
This is when huge protests will be held across the city, with 50,000 people expected to turn up on Friday afternoon - parading to Trafalgar Square through central London.
While Mr Johnson may now be a backbencher, Mr Trump said he hoped he would still see the former foreign minister - another blow to the fragile position of Mrs May.
Trump is doing his best to avoid the mass protests planned for his controversial trip, which will include talks with May, tea with Queen Elizabeth II and a private weekend in Scotland.
Various protests and demonstrations have been organised in Bristol, Newcastle, Leeds, Cambridge and Cardiff after Trump arrives on Thursday.
A small demonstration is expected to take place near Blenheim Palace in Oxfordshire on Thursday, the venue for Trump's black-tie dinner with Prime Minister Theresa May.
Mr Trump is expected to meet Prime Minister Theresa May today - days after saying the United Kingdom was "somewhat in turmoil".
For protesters in Edinburgh they have a particularly varied day to look forward to.
"Give us your tired and your oppressed and we'll divide you from your children", he said mockingly of Mr. Trump's policies.
Prime Minister May has abundant reasons to seek a close relationship with Mr. Trump - not least, the United States will be an even more vital trade partner once Britain leaves the European Union next year - but it is an uneasy embrace, given her opposition to many of his key policies.