He was scheduled to perform, publicist Tammy Brook told CNN, and Rolling Stone magazine spoke to a source who said 21 would take the stage with Post Malone to perform their hit, "Rockstar." The song earned two Grammy noms.
Before collaborating with Post Malone -- and long before his second album topped the Billboard 200 -- 21 shot into hip-hop's collective conscience in 2016 with two words: "Issa Knife."
The phrase was repeated from the city to the suburbs, made into memes and ushered the rapper toward mainstream stardom. He'd go on to name his debut studio production "Issa Album."
The face tattoo was an homage to a friend who was murdered. It was as much a tribute to his fallen fellow gang member as it was a symbol of what he represented to hip-hop: a young rapper with a raw, rough but real story of growing up in Atlanta's drug-dealing areas, known as traps.
The internet was not kind after 21's arrest, and a parade of Twitter memes ensued.
One stated he wrote his rhymes with a feather quill, and another quipped that when he rapped about having shooters, he wasn't talking about fellow gangbangers, but rather, British redcoats.
"Issa Joke" one opined about 21's rap career. "+44 Savage," another user poked fun, employing the United Kingdom's international calling code.
"Englanddd?" another Twitter user wrote mockingly. "ATL streets done with."
In an industry where an artist's credibility and success is often defined by how authentic their struggle was growing up, 21 was dragged and roasted. An ICE spokesperson went so far as to say 21's "whole public persona is false."
Those who know him, however, were furious at the suggestion and quick to defend him.
"I don't know what the world done came to," Duct Tape Entertainment CEO Big Bank pondered aloud in one Instagram post. "When did it become funny to laugh at a n***a who get locked up?"
"You talking about where a n***a born at? That s**t don't matter, n***a. Wherever you bust your gun at, wherever you got the game at, that's where you from, man," Big Bank said in a video post.
"Savage Zone 6 n***a for life," he added, referring to the Atlanta Police Department's designated Zone 6 -- home to the careers of Gucci Mane, Childish Gambino and 21's Epic Records labelmate, Future.
Big Bank's response to the internet's insults was a microcosm of how hip-hop came to 21's defense. To them, none of what the world was saying about 21 seemed to matter.
CNN's attempts to reach 21's family by phone were unsuccessful. Another effort -- to join 21's friends for a tour of the rough-and-tumble neighborhood in which the rapper grew up -- fell through when his friends declined to escort a reporter into the area, saying, "The situation was too hot."
In 2006, 21's parents failed to renew his visa. He's been living in the United States illegally ever since, according to immigration officials.
In October 2014, Abraham-Joseph was convicted in Fulton County on counts of marijuana possession with intent to distribute, possession of a firearm or knife during the commission of certain felonies and manufacturing, delivery, distribution and/or possession of a controlled substance with intent to distribute. The rapper's representatives say the conviction was expunged.
While his publicists say they have been working on his immigration status for at least two years, the majority of people found out about his international roots on Super Bowl Sunday.
For many, the timing of his arrest seems suspicious.
"There's a lot of pieces that lead you to believe this wasn't an accident," said Anastasia Tonello, president of the American Immigration Lawyers Association. "This could be a nice case for the government to show that they are tough on immigration."
She continued, "What I find very interesting in his case is that he has deferred action. His application for a U-Visa defers any action on him based on his application. Typically someone like that, ICE would not actively look to deport him. ICE would need to request to put him in removal proceedings."
The visa application was filed in 2017, Kuck said. That's four years after the rapper reportedly was shot six times during an incident in which his friend died.
A U-visa is available to those who have been the victims of a crime in the United States, have suffered physical or mental injury as a result of a crime and who are "helpful to law enforcement or government officials in the investigation or prosecution of criminal activity," according to ICE.
21 wasn't the target of the operation that landed him in the custody of immigration officials, a law enforcement source with knowledge of the arrest said.
It was another rapper, Young Nudy, who was the target of a criminal arrest, the source said, and 21 was seemingly caught in the middle.
In the days since he was taken into custody, rallies have been held in his name, petitions calling for his release have been widely circulated and Jay-Z is among the hip-hop luminaries who have backed him. But will it be enough to keep him from being deported?
"It depends if this is a means to perpetrate more fear and insecurity into immigrant communities by the Trump administration," Tonello said. "If they want to use an example of him to frighten immigrant communities, they can do that."
"Atlanta is one of the high rates of deportation. There are low rates for immigrants winning their case, but he has US citizen children, he was the victim of a crime, he has done philanthropy. ... The judge will balance that."
CNN's Eliott C. McLaughlin contributed to this report.