The drive-by shooting in Las Vegas in 1996 resulted in four gunshot wounds for the hip-hop legend. His killer's identity is still unknown.
According to sources talking to the AP news agency, Las Vegas police detained a guy on Friday in connection with his death.
Soon, a police press conference is anticipated.
A week after being shot four times while waiting at a red light in his car, he passed away on September 13, 1996, at the age of 25.
Separately, ABC News reported a senior law enforcement official who said charges would be unveiled on Friday afternoon and that a suspect had been detained in connection with Shakur's slaying.
The news comes after Las Vegas police allegedly raided a gang member's residence in July in pursuit of clues regarding Shakur's passing.
Numerous films were inspired by the rapper's passing, one of the most celebrated in hip-hop.
In response to the arrest, radio personality Mike Muse told ABC News: "Tupac was a brilliant rapper, poet, and actor. His songs still serve as such a model for culture and society today.
This explains why the question of what truly happened to him after his death has hung over us for so long.
In 1991, Shakur, whose stage name was 2Pac, released his debut album.
He sold more than 75 million records worldwide and had hits on the charts with songs including Changes, All Eyez On Me, and California Love.
The rapper was honored with a posthumous star on the Hollywood Walk of Fame in June of this year.