A$AP Rocky is a US rapper who released his debut album, Long.Live.A$AP, in 2013.
He has been nominated for two Grammy awards and collaborated with the likes of Drake, Kanye West and Kendrick Lamar.
He is currently on trial in Sweden and has been in custody there since 3 July, accused of assaulting a 19-year-old man, Mustafa Jafari, on the evening of 30 June.
As a well-known hip-hop artist, his trial has made international headlines and attracted attention from celebrities including Diddy, Justin Bieber, Kim Kardashian West, Jada Pinkett Smith, Rod Stewart, Cara Delevigne and Post Malone.
More than 600,000 fans have signed a #JusticeForRocky petition set up online.
And following a call from Kanye West, who he has met in the past, the US president himself became involved.
Donald Trump asked Swedish Prime Minister Stefan Lofven to help free the rapper, but the politician said he could not interfere in a legal case.
Trump later tweeted messages saying he was “very disappointed” in Mr Lofven and demanding: “Treat Americans fairly!”
Mr Trump has said he would personally vouch for bail, although Sweden does not have a bail system.
The president has sent ambassador Robert O’Brien, the US special presidential envoy for hostage affairs, to Sweden to monitor the court proceedings.
A$AP Rocky, real name Rakim Mayers, has given evidence in court, saying Jafari followed him and his entourage and that his security guard “begged” him to leave them alone.
The trial is due to end on Friday.