When Dakota Fanning learned she'd be playing Sean Penn's daughter in I Am Sam — opening Dec. 28 — she reacted like any seven-year-old would. "We had such a small apartment that there wasn't anywhere to run around," she recalls, "so I jumped up and down on the bed! And then I called my grandmother."

If Fanning keeps snapping up plum parts — she just wrapped Kevin Bacon's 24 Hours and is now shooting Sweet Home Alabama with Reese Witherspoon — the tyke will need a good long-distance plan! Of course, her thespian ambitions are no surprise to Granny. "I've been a ballerina since I was two," she smiles, "but I've always wanted to be an actress." Sometimes, though, she's taken her make-believe games to dramatic extremes! "I would go through 'childbirth' all the time," she says. "I'd put a pillow up my shirt and pretend that I'm pregnant."

Yikes! Fortunately for her, Mommy opted to take little Dakota to see a talent agent rather than a child psychiatrist. That wise judgement call paid off: The Broadcast Film Critics Association (BFCA) has just nominated Fanning — along with A.I.'s Haley Joel Osment and Harry Potter's Daniel Radcliffe — for best child performer.