AceShowbiz - French Montana stopped his Wireless Festival set to show his support for arrested rapper J Hus.
The 23-year-old was due to perform at the festival until he was arrested for carrying a knife in east London last month.
Organisers announced on Tuesday that they were dropping the Did You See artist from the line-up due to "unforeseen circumstances", was replaced by Krept and Konan.
Montana, who performed on Saturday, gave a shout out to J Hus, and covered his track Did You See in his absence.
"I had to rep my boy tonight cos' he wasn't going to be here tonight," he told the crowd.
Montana also wore an England football shirt in honour of the team's World Cup quarter-final match against Sweden. "Y'all see what I'm wearing?" he asked festivalgoers.
J Hus, real name Momodou Jallow, was taken into custody on 21 June after police found a weapon in his car after he was pulled over in Stratford, east London.
According to British publication The Guardian, the rapper was charged with possession of a knife or bladed article and was released on bail earlier this week, having posted a $132,000 (£100,000) bond.
Under the bail terms, he is reportedly forbidden from entering certain areas of London, including Hackney, Tower Hamlets, Barking and Dagenham. He faces a pre-trial hearing on 20 July.
The Bad Boys hitmaker took to Twitter on Wednesday to thank family and fans for their ongoing support and apologise for any inconvenience.
👌 u already know my g https://t.co/zHt9P39Q0H— French Montana (@FrencHMonTanA) July 8, 2018
"Been seeing a lot of support from fans, artists and family," he penned to his 251,000 followers. "I appreciate everything, Trust me. Shoutout my team for the work behind the scenes. Also sorry for the cancelled live dates I've missed out on."