Driving Lessons (2006)

Teenage Ben (Rupert Grint) lives a sheltered life thanks to an overprotective mother (Laura Linney) and a weak-willed father (Nicholas Farrell). The youth takes a summer job as the assistant to Evie Walton (Julie Walters), an aging actress. At first the job is simple, but then Evie presses Ben into service as her chauffeur, even though he lacks a license. Ben must take the first step into adulthood, and learns how to have fun along the way.