The march will start at noon tomorrow by the Hilton Hotel on Park Lane with demonstrators marching to Parliament Square to hear speeches in support of a new vote from 2pm.
Organisers want the public to have a final say on the British government's Brexit deal with the European Union, arguing that new facts have come to light about the costs and complexity of Britain's exit from the bloc since Britons voted to leave in 2016.
There are now 2 million young people in this country who are entitled to vote but had no say at any point over the Brexit process.
The People's Vote campaign said its stewards estimated the size of the crowd to be around 570,000.
"We want everyone to write a letter to their MP, whether it's Anne Main or someone else, and demand a vote on the deal".
The pro-EU newspaper's online petition demanding a binding vote on any deal agreed before the March deadline has been signed almost a million times.
The UK should leave the European Union on 29 March 2019.
Britain is scheduled to leave the European Union in March, and the Bank of England has warned that economic chaos will follow if the sides fail to reach a deal.
"Instead this week she has shown that she is going to persist in trying to use Brexit simply to further her cause for a second independence referendum". She said recently SNP MPs would back a new Brexit referendum. This contrasted with the nation as a whole, as 52 percent voted to leave.
"The idea that you should have a second referendum would be incredibly damaging most of all to the trust in democracy from people up and down this country", Richard Tice, founder of the opposing Leave Means Leave campaign, said.
She said that when she is "confronted with tough choices" over Brexit, she does not think about "what the implications are for me" but instead what is best for United Kingdom families.
"What could be more democratic, what could be more British than trusting the judgement of the British people?" asked London Mayor Sadiq Khan asked by the BBC what his message for Theresa May was as he joined the #PeoplesVote march.
Corbyn's absence was despite delegates at Labour's recent conference supporting a motion to keep the People's Vote option on the table, while acknowledging their preference would be for a general election.
The EU said Thursday that it was ready to extend the length of the transition period that is created to smooth the UK's exit from the 28-nation bloc next year.
The march comes as pressure builds on Prime Minister Theresa May over her negotiating strategy with just over five months until Britain is due to leave.
Khan earlier tweeted a picture of himself on the march, saying he was supporting it because "a bad Brexit could have a huge impact on Londoners".
"We would have to meet minimum income rules and I am self-employed", the 53-year-old said. "It is as if we are driving towards a cliff, but won't face up to the reality that the road we have chosen will take us over the edge".