Thousands of people are expected to join a march for Scottish independence through Edinburgh.
It will begin in Holyrood Park and end with a rally in The Meadows.
Joanna Cherry, the SNP MP who led the legal fight against Boris Johnson’s decision to suspend parliament, is among those who will address the crowd later.
A similar event in the capital last year drew about 20,000 people, according to official estimates.
It is the latest in a series of similar marches through towns across Scotland, organised by All Under One Banner.
Supporters are scheduled to leave Holyrood Park at about 13:00 before taking a route of about 1.8 miles (3km) to The Meadows.
They will follow Queens Drive, Horse Wynd, Canongate, High Street, Lawnmarket, George IV bridge, Forrest Road and Middle Meadow Walk.
It is likely to be a colourful and noisy march, with organisers urging participants to take flags, banners, pipes and drums on their journeys.
A number of high-profile supporters of Scottish independence have been lined up to speak at the rally.
As well as Ms Cherry, they include comedian Janey Godley, broadcaster Hardeep Singh Kohli, and ex-MSP Tommy Sheridan.