Inside Sandra Bullock's New Life
updated 08/10/2011 AT 11:00 AM EDT
•originally published 08/10/2011 AT 08:00 AM EDT
Credit her 19-month-old son Louis, her sense of humor and her decision to jump back into the acting world in a big way.
"She was very keen to get back to work," says Stephen Daldry, who directed her in Extremely Loud and Incredibly Close, one of two dramas the actress, 47, has filmed since last fall.
"She threw herself in with her usual enthusiasm and energy, and she was very relaxed," he added. "She had little Louis with her, and it was a very familial environment on-set."
Bullock, who also just wrapped the astronaut drama Gravity, has been keeping a low profile as she passes emotional milestones: the one-year mark of her divorce from Jesse James, and this month's anniversary of her official adoption of Louis.
As she steps back into the spotlight, her new life is a joyful one. "She's glowing," says her Extremely Loud costar Reagan Leonard.
For more about Bullock's life as a mom, the truth behind romance rumors and a first look at Extremely Loud and Incredibly Close, pick up the new issue of PEOPLE, on newsstands Friday