The stars of Harry Potter have gone from children to young adults before our very eyes. But when you actually compare then (Sorcerer's Stone) and now (Half-Blood Prince), you may not believe your eyes. See for yourself.

Daniel Radcliffe, 19, shows his serious side in his new Harry Potter film — or at least looks as serious as he can in those ridiculous-looking glasses his character refuses to upgrade.

Little Harry proudly wears his Hogwarts house's colors — red and gold — after the magical Sorting Hat decides he belongs in Gryffindor.

Emma Watson, 19, plays the brilliant best bud of Harry, Hermione Granger, who is starting to look at her guy friends a bit differently in Half-Blood Prince. Just ask Ron.

What a tiny Hermione! Even in her first year, this brilliant spell-caster knew everything (except how to tone down the hair frizz).

Rupert Grint, 20, plays newly minted ladies' man Ron Weasley. Perhaps he should lose the Hugh Hefner look, though.

What an adorable little carrot-top Ron was during his first trip on the Hogwarts Express. And who could forget his little rat Scabbers (aka Peter Pettigrew)?

Tom Felton, 21, loves to bully his Hogwarts peers as Draco Malfoy. Ever wonder how he finds time in all that terrorizing to bleach his hair the perfect shade of platinum blonde?

It's hard to imagine this impish little boy could be such a little trouble-maker. But as much as he likes to run his mouth, he's really just a big ol' wuss.

Eighteen-year-old Bonnie Wright's role as Ginny Weasley has developed quite a bit over the past few years. Perhaps it's because she catches the eye of a well-known Hogwarts student in Half-Blood Prince (no names, of course).

While Ginny hasn't changed as dramatically as the rest (most likely because she can't let go of that long, parted 'do), you can still see how innocent her freckled-face was back in her early Hogwarts days.