Grandson claims he was banned from bringing Bob Vylan out onstage at the O2 Forum Kentish Town.
The singer, whose real name is Jordan Benjamin, brought his Inertia tour to the Academy Music Group's London venue on March 2, and he was planning to bring out the duo's frontman Bobby Vylan as a "surprise guest".
He wrote on his Instagram Story: “As we got ready to rock the O2 Forum Kentish Town tonight, we were informed right before the show that our surprise guest Bobby Vylan would not be allowed in the venue or onstage.
“When I threatened to pull out of the show they said it was out of their hands and due to the local police’s fear of protestors impacting the safety of the audience.”
Grandson insisted he was faced with a decision between telling his fans to "go home", or accept the decision.
He continued: "I was put in the position where I had to either tell the 2,000 people that travelled to the show and paid a ticket tonight to go home, or have my OWN freedom as an artist to invite whoever [the] fuck I want onto the stage and say whatever the f*** I want be infringed on.”
Ultimately, he decided to still perform the gig as a mark of respect for his fans, as well as giving them "a place to feel the love and community that a Grandson show is ultimately about".
However, he insisted the whole situation felt "gross", as he took another shot at the venue.
He added: “You benefit from the ticket sales and take a merch cut from outspoken artists but then aren’t prepared to protect our words.
“Really shameful and disappointing.”
He explained the situation to the audience on stage, and shared the video on social media.
Grandson was actually due to take punk-rap duo on tour in the US last year, but their visas were revoked after controversary over their set at Glastonbury.
Bob Vylan's performance, which was aired live on the BBC, saw them leading the crowd in chants of "Free, free Palestine" and "death to the IDF" in reference to the Israel Defense Forces.
They were also the subject of a criminal investigation, which was dropped, and their agent parted ways with the act.
At the time, Jewish artist Grandson said in a statement: "Censorship of art is a tactic of control. They blame artists and activists and not those who responsible for the conditions we rage against.
"From the death spiral of corporate greed and climate change to the genocide of Palestinian lives, the music and the artists are not the problem, we are the symptom of a sick world.”
He also said he was "deeply offended by the conflation of criticism against a military force known for their indiscriminate violence with antisemitism".
He continued: "Bob Vylan are the one feature on my album and that feature will go on. If they have the opportunity to come to the United States, they will join us on the Inertia tour as planned.”
