Sistine Stallone is ready to take on the family business, making her acting debut in “47 Meters Down: Uncaged” — though she was more than a little reluctant at first.

“Absolutely not. Oh my God, no,” she told Variety when asked if she’d secretly dreamed of becoming an actor. “I still think acting is something that you’re born with and I think the greatest actors today, they don’t need training, it comes naturally to them. It’s like being a naturally good singer….I don’t think that’s me at all.”

But it stands to reason that Stallone was born with some natural charisma as the daughter of “Rocky” star Sylvester Stallone, whether or not she recognized it. The 21-year-old is the middle daughter of the Oscar nominee and wife Jennifer Flavin, but she says that being the child of a famous movie star initially turned her off from the profession.

“Growing up in a family with such an iconic actor, the last thing I wanted to do was act because that was all that was essentially discussed that in my household and I was like, ‘Anything else, I’ll try anything else that I want to do,’” she said, explaining that she first tried her hand at modeling before focusing on college.

But when the opportunity presented itself to try out for a role in the “47 Meters Down” sequel, she jumped at the chance and enlisted her mother to help prepare for the audition.

“I went into acting, not expecting to book a role, [but] just to make myself uncomfortable and do something a little bit different for myself,” she recalls. “I never thought it was something that I would do, ever.”

Stallone ultimately landed the role of Nicole, a teen who sneaks off to go cave-diving with a group of high school friends (Sophie Nelisse, Brianne Tju and Corinne Foxx) and ends up facing off against sharks. Like Stallone, Foxx is the progeny of another extremely famous celebrity (Oscar-winner Jamie Foxx) and both young women served as Golden Globe Ambassadors.

“Knowing that she was going to be doing the film with me was such a relief,” Stallone admitted. “It was really, really nice to have a familiar face.”

Aside from the nerves that come along with booking your first screen role, Stallone had other fears that needed to be calmed. Though the actress loves shark movies (listing “Soul Surfer,” “The Shallows,” “The Meg” and the original “47 Meters Down” as favorites), she prefers to stay on land.

“I hate going in the ocean myself because of sharks, so [shark movies] give me this reality of what it would be like, and now that I’ve kind of essentially lived it a little bit, I’ve confirmed that I will never go back in the ocean,” she explained.

Putting the exciting opportunity before her fears, Stallone embraced the physical nature of the role and dove into training to appear realistic on screen, saying that’s the aspect that attracted her most. “We were very athletic growing up. My dad basically trained us like boys when we were little, so being able to physically challenge myself and to be able to do crazy stunts and not use my stunt double was super exciting for me.”

“I worked out with a trainer for a month before [filming] to get my swimming endurance up because I wasn’t a very strong swimmer and I really want to do a work on that a little bit,” she continued, added that the cast had an additional week of training once arriving on location in the Dominican Republic.  The actress ultimately obtained a scuba diving license, though she doesn’t think she’ll ever use it. “Maybe in a pool,” she quipped.

And like her character, Stallone claims to be a bit of an adrenaline junkie. “The scene of us jumping off of the cliff, I was begging the director [Johannes Roberts], I’m like, ‘Please let me do it. Like I don’t want my stunt double doing anything,’” she recalled, saying Roberts eventually caved and let her do the stunt. “Stuff like that, it really does excite me and I want to essentially … prove to myself that I’m more than capable of doing anything that’s kind of physically challenging.”

While Stallone isn’t sure she wants to pursue acting full-time, she’s grateful for the experience and carries a particular piece of advice from her father into any job she does: “Arrive early, stay late and work as hard as you can in between and you’ll always find success. If you’re doing that while treating people with respect, it’s so simple that really what more could anybody ever ask for?”

“47 Meters Down: Uncaged” hits theaters on Aug. 16.