Kneecap band member Liam Óg Ó hAnnaidh - known by his stage name Mo Chara - who has been charged with a terrorism offence, has been granted unconditional bail until his next hearing on 20 August.
Chief Magistrate Paul Goldspring told Mr Ó hAnnaidh he must attend court on that day.
He is alleged to have displayed a flag in support of Hezbollah at a gig at the O2 Forum in Kentish Town in north London on 21 November last year.
He was accompanied to Westminster Magistrates' Court this morning by his two other band members, JJ Ó Dochartaigh, whose stage name is DJ Próvaí, and Naoise Ó Cairealláin, whose stage name is Móglaí Bap.
Hundreds of fans, along with journalists, crowded against the doors of the court building as they waited for the performer to leave. He then went into a side room to speak with lawyers after the hearing.
Ahead of the hearing, supporters greeted the band as they slowly made their way to the entrance of the court building.
The band were wearing "Free Mo Chara" T-shirts.
Supporters gathered outside the court building from early morning, holding placards saying "Free Mo Chara" and "Defend Kneecap".
A mixture of Palestinian and Kneecap flags were being held by some of the crowd, and cheers were heard after an ad van drove past displaying the slogan "More Blacks, More Dogs, More Irish, Mo Chara".
Hundreds of protesters turned out in support of Kneecap
Last month, British police confirmed that Mr Ó hAnnaidh was charged with a terrorism offence.
London's Metropolitan Police was made aware of an online video from the event last April.
An investigation was then carried out by the Met's Counter Terrorism Command.
The 27-year-old was charged last month with displaying a flag "in such a way or in such circumstances as to arouse reasonable suspicion that he is a supporter of a proscribed organisation".
Mr Ó hAnnaidh has denied the allegations, describing them as "political" and intended to "silence" the group.
Kneecap has vowed to "vehemently" defend themselves and insist that the flag was "thrown" onto the stage.
They have also described the charges as a "carnival of distraction" from what is happening in Gaza.
In a social media statement last month, the group stated that the "anti-terror" law was being used against them "to restrict our ability to travel. To prevent us speaking to young people across the world. To silence voices of compassion. To prosecute artists who dare speak out".
Last week, Kneecap announced Mr Ó hAnnaidh's legal team.
It comprises Gareth Peirce, solicitor for Gerry Conlon and the Guildford Four, WikiLeaks founder Julian Assange, and Rosalind Comyn, who has represented Extinction Rebellion protesters in court.
His team also includes Darragh Mackin from Phoenix Law, Brenda Campbell KC, Jude Bunting KC and Blinne Ní Ghrálaigh KC, who was part of South Africa's legal team in its case against Israel, accusing the country of genocide.
The band are due to play a headline gig at Dublin's Fairview Park on Thursday, 19 June.
Additional reporting: PA
