Sistine, 18, worked the catwalk in an oversized black vest adorned with gold buttons and black heels.
"Thank you so much @stefanogabbana @dolcegabbana for always being so kind and generous. I am so unbelievably grateful for this opportunity. I ? my DG family??," she captioned a photo of her runway look on Instagram.
The Stallones weren't the only up-and-comers who rocked the runway, which epitomized Dolce & Gabbana's new social media hashtag, #DGMillennials. Lionel Richie's daughter, Sofia Richie, and social media star Cameron Dallas also strutted their stuff.