Charlize Theron -- My Alleged Stalker Brought Me Flowers

Charlize Theron says an unexpected floral delivery turned into a nightmare when a guy refused to leave until he saw her face-to-face ... so she called the cops.

Law enforcement sources tell TMZ a man showed up at Theron's home in the Hollywood Hills on Sunday afternoon with a bouquet of flowers.

We're told he rang the buzzer at the front gate and Charlize instructed him to "just leave them," but she claims he refused to take off.

Charlize called police, and the guy got arrested for stalking.