Jada Pinkett Smith: Good Genes or Good Docs?

You don't need a Nutty Professor to tell you how great Jada Pinkett Smith looks.

Here's the 23-year-old "Set It Off" former blonde back in 1995 (left) -- and 17 years later, the 40-year-old "Madagascar 3" beauty in NYC this week (right).

Where there's a Will, there's a way ... to age fabulously.