"I never thought it could happen, this rappin' stuff/ I was too used to packing gats and stuff," Biggie famously spit on his breakout hit "Juicy."

The thing with Big is, that's what he really believed — especially when he learned his first child was on the way. His then-girlfriend, Jan, got pregnant, and the high school dropout had to become head of the household really fast. So the MC, then known as Kwest, ditched the rhymes and did what he always did: hit the block to deal drugs.

Eventually, Big relocated his pharmaceutical sales to North Carolina. "Figured out nicks went for 20 down South," he rapped on Ready to Die's "Everyday Struggle."

The fast life, however, caught up with him, and he got arrested, spending nine months in jail for selling crack. Biggie relied on his faith while he was incarcerated, often reciting Psalm 23, which he later tattooed on his arm.

Upon his release, Big returned to Brooklyn. In this exclusive clip from "Notorious" (due in theaters Friday), the former dealer reunites with his crew and, after taking a puff from a blunt, grabs the microphone. Kwest then transformed into Biggie Smalls before everyone's eyes.

"Your rhymes got tight," a giddy Lil' Cease says.

Rap legend Big Daddy Kane's DJ, Mister Cee, was on hand to witness the moment. "I know people," Cee tells Jamal "Gravy" Woolard's Biggie, prompting him to consider his professional potential.

DJ 50 Grand cued the record up again, and Big spit what would become the demo cut "Microphone Murderer," which is featured on the "Notorious" soundtrack. The song was recorded in 1991, and it landed Big a spot in The Source magazine's then-coveted column "Unsigned Hype." Shortly after, Biggie would sign with Diddy and Bad Boy Records.

MTV News has some B.I.G. things on the horizon surrounding "Notorious" — stay tuned for more this week!