Millie Bobby Brown — Stranger Things to Beauty Mogul

Brown became a global star at 12 as Eleven in Stranger Things (2016). By 15, she was a UNICEF Goodwill Ambassador (the youngest ever). At 16, she launched Florence by Mills — a clean beauty brand targeting Gen Z, now sold in 10,000+ retail locations including Ulta and Boots. She starred in Enola Holmes ($400 million combined for both films). At 21, she's already a beauty entrepreneur, franchise lead, and UN ambassador. The Stranger Things kids were supposed to be a flash in the pan. Millie built a business while her costars were still doing conventions.