Sure, they're taller than they were when they first enrolled in that school, but they're still students, with much to learn in matters of sorcery and sexuality, half-hatched creatures seeking some direction.
It's a romantic illusion. And if fans want to buy into it, they should probably not pay attention to the stars' real lives.
For adolescent actors, all of that's normal. For wizards in training, not so much. Shouldn't Grint's alter ego, Ron Weasley, be able to slay the H1N1 virus with his magic wand? For that matter, shouldn't Jamie Waylett, who plays Hogwarts' tough guy Vincent Crabbe, be able to banish charges of illegally growing 10 cannabis plants?
Just kidding, of course. But the fact remains: The children who debuted in "Harry Potter and the Philosopher's Stone" in 2001 and went on to appear in all five sequels have grown into characters that don't always jibe with the personalities J.K. Rowling's books gave them.
Ahead of the sixth Harry Potter installment, due in theaters July 15, check out how three major players have changed before audiences' eyes:
The cute kid with the round glasses has grown into a Hollywood heartthrob and one of the most promising young actors of his generation. Radcliffe, 19, began building his resume beyond the Harry Potter franchise early on -- in 2002, he appeared as a guest in the London production of Kenneth Branagh's "The Play What I Wrote." Radcliffe jumped into theater in earnest when he took the lead role of a horse-obsessed stable boy in the 2007 revival of "Equus" and appeared nude on stage.
Though he shocked his fans, Radcliffe made the right move -- he won critical acclaim for "Equus" and his role in the 2007 indie movie "December Boys," proving his viability beyond the Harry Potter series, which will wrap up in 2011. Radcliffe's also one of the richest actors in his coterie: According to Forbes, he makes $25 million per Potter movie.
She landed the role of Hermione Granger at age 9 with no experience save for school plays. Now, no one can contest Watson's status as an actress. Watson first branched out from Harry Potter in 2007, starring in the BBC TV movie "Ballet Shoes." She went on to voice the character of Princess Pea in the 2008 animated comedy "The Tale of Despereaux."
Watson ventured away from the screen with her latest project: posing for high-end fashion house Burberry's autumn/winter 2009 collection.
While Watson intends to attend college, she also plans to continue acting, and given the right role, she would go nude like Radcliffe.
"I'm not getting my kit off any time soon, but it is part of my job," she said in a 2008 interview.
His quirky expression and mop of red hair keep his boyish appeal intact, but the 20-year-old Grint has made moves to ensure he'll still be a force in the acting world well into his adult years.