Wole Soyinka arrived the court ahead of the proceedings scheduled to commence 9 am on Wednesday.
Others including the former senator representing Kaduna Central, Shehu Sani later joined him.
an activist,called "Sani" who exchanged banters with the playwright, later took a seat behind him.
A former Chairman of the National Human Rights Commission, Prof. Chidi Odinkalu, and another activist, Deji Adeyanju, later arrived.
The court had yet to commence sitting as of the time of filing this report at 9.44 am on Wednesday.
Department of State Services had in August 2019 arrested Sowore and his codefendant, Olawale Bakare, in respect of the protest.
They were subsequently charged with a treasonable felony for allegedly planning to topple the regime of the President, Major General Muhammadu Buhari, among other counts including abusing the President.
They were held in custody for over four months until mounting domestic and international pressure forced the government to release them in December.
Justice Ijeoma Ojukwu had fixed Tuesday for the commencement of trial but had to adjourn till Wednesday due to her official assignment elsewhere.