London-based Anjem Choudary is accused of inviting support for the banned group on social media from June 2014 to March 2015. The 48-year-old is being held on remand in prison and appeared in front of a packed Old Bailey court in London via videolink today.
A plea hearing will take place before the trial begins on January 11. Another man, Mohammed Rahman, 32, is accused of the same charges and both the accused had previously indicated they would be pleading not guilty.
Choudary and Rahman appeared before Justice Saunders from high security Belmarsh prison for their first hearing. Dressed in a white robe, Choudary spoke only to confirm his name and was represented by lawyer Blinne Ghralaigh. The judge set a plea and case management hearing for December 11.
The trial, which will take place at an as yet undecided court in London, is scheduled to last between three and four weeks. Sue Hemming, of the Crown Prosecution Service (CPS), said: "It is alleged that Anjem Choudary and Mohammed Rahman invited support for ISIS in individual lectures which were subsequently published online.
"Criminal proceedings have now commenced and both men have a right to a fair trial. It is extremely important that there should be no reporting, commentary or sharing of information online which could in any way prejudice these proceedings."
Choudary is the former UK head of Islamist group Al Muhajiroun, also known as Islam4UK, which was banned in 2010. He remains a controversial figure in Britain, often appearing on news channels airing extremist views.