Since its release in 2003, Curtis “50 Cent” Jackson’s “In Da Club” has gone on to rival “Happy Birthday to You” as the most popular song to celebrate another lap around the sun. While speaking to PEOPLE about his new film, heist-thriller Den of Thieves co-starring Gerard Butler and Pablo Schreiber, the multi-talented artist and entrepreneur reflected on the 15th anniversary of his career-launching smash.

“Simplicity is a big key to hit music,” Jackson says of its staying power. “Don’t overthink things, just organically see what you feel when the production comes in. Like, ‘Go shorty, it’s your birthday.’ It’s not rocket science. It’s a simple statement.” More importantly, the track has a built-in premise that ensures practically infinite relevance. “Every day is someone’s birthday so it sticks around, right?”

Jackson’s debut long player, the Dr. Dre and Eminem-produced Get Rich or Die Tryin’, would become one of the best-selling albums of the decade. It also provided the title of Jackson first acting vehicle in 2005, built largely around experiences from his own life — including the 2000 attack in which he was shot nine times. From there he consolidated his status as a bankable star of action flicks and tried his hand at screenwriting, penning the crime noir Before I Self Destruct (2009), shoot-em-up thriller Gun, and All Things Fall Apart, a drama that saw him lose more than 50 lbs. to play a cancer patient.

He says that it was the “endless possibilities” in movies that drew him into his second act as leading man. “I’ve been doing music since 1997. It’s first nature for me. The challenge of being part of a film project is really exciting. There’s no constraints in film; you can be anything.”

To read more about Curtis “50 Cent” Jackson’s new movie Den of Thieves and his hip-hop legacy, pick up the latest issue of PEOPLE, on newsstands Friday.

The endless series of rewrites and reshoots required to craft a movie are at odds with his open-ended method of making music.

“If you used the process they use in filmmaking in music you would destroy the song,” he says. “[I] put the best possible musicians in the room, start the drum sequence, and before you know it it’s a jam session. But if you said, ‘Let’s just do it and do it and do it and do it…’”

As evidenced by the deceptively simple refrain of “In Da Club,” the best ideas often come quickly.

“People think the more they work on the song the better the song is, but that’s not necessarily true. You could have written the right verse to the song three passes ago, and now you’re still doing some other s— to it and it’s not getting better. You’re just wrecking your brain coming up with things.”

Den of Thieves is in theaters now.