Owen Jones and the group Stop Trump, a coalition of anti-Trump MPs, activists, trade unionists and celebrities, are organising the demonstration at Parliament Square, which Facebook currently has 13,000 people listed as attending.
The rally, which has been arranged to coincide with the parliamentary debate on Trump’s state visit, will run from 5pm to 8pm.
A further 31,000 people have said they are interested in attending.
A statement on the event’s Facebook page reads: “We are calling for a nationwide day of action to stand up and say no to the future of hatred, racism and division that Donald Trump is trying to create – and to say no to the disgraceful complicity of Theresa May and the British government in supporting him.”
The Stop Trump Coalition have linked their events across the country with One Day Without Us, a campaign designed to “celebrate the contribution that migrants have made to the UK”.
One Day Without Us organisers said in a statement: “We recognise that tens of thousands of people across the country have been moved to act in response to Trump’s anti-migrant and anti-Muslim rhetoric, and we have been in discussion with the coalition organisers to ensure that our two campaigns complement each other.
“The Stop Trump Coalition organisers have shown an admirable willingness to facilitate the many events we have already planned across the country.
“They share with us a common determination to uphold the rights of migrants and defend the rights of EU nationals.”
The statement added: “Our two campaigns share a common rejection of the politics of hatred and division and a common refusal to accept the scapegoating of migrants.
“Between us, we can make Feb 20 the greatest statement of solidarity with migrants in UK history.
“Let us seize this opportunity, and stand alongside the migrants we have known as colleagues, co-workers and friends. Let us celebrate their presence and show our own politicians – and Donald Trump – the kind of society that the UK has already been – and can still be.”
The Metropolitan Police said they are aware of the demonstration and that they have an “appropriate plan in place”.
More than 1.8 million people have signed a petition calling for the US president’s proposed state visit to be cancelled. The Government has rejected the petition.
Frankie Boyle, Lily Allen and Paloma Faith are among those to lend their support to the Stop Trump campaign.
National Day of Action events:
London: 6pm Parliament Square
Edinburgh: 1.30pm The Mound
Glasgow: 6pm George Square.
Leeds: 1pm Briggate
Manchester: 12.30pm Piccadilly Gardens
Liverpool: 6pm The Lyceum
Liverpool: 12.30pm John Lennon Peace Memorial Quay
Lincoln: 6pm Cathedral Square
Nottingham: 5.30pm Forest Recreation Ground
Leicester: 6pm Town Hall Square
Cambridge: 5.30pm Market Square
Hereford: 6pm High Town
Swansea: 5.30pm Castle Square
Cardiff: 6pm Queen Street
St Davids: 6pm Cross Square
Bridport: 6pm Buckydoo Square
Exeter: 5.30pm Bedford Square
Bournemouth: 6pm The Square
Reading: 6pm Queen Victoria Statue
Brighton: 12pm Clock Tower
Canterbury: 5pm Dane John Gardens
Hitchin: 5.30pm Market Square
Newcastle: 12.30pm Greys Monument