Will Smith -- Good Genes or Good Docs?

Will Smith's good looks are still fresh!

Here's a 22-year-old version of the "Fresh Prince of Bel-Air" back in 1990 (left) and 28 years later ... the now 49-year-old "Independence Day" icon taping a late night talk show appearance earlier this year (right).

U.S.A., U.S.A., U.S.A.!

The question is ...