It's the first 'relationship' Pitt has had since splitting wife wife Angelina Jolie two years ago, after he was reportedly introduced to Theron by her ex-fiance, Sean Penn.
“They have been casually seeing each other for nearly a month now. They’ve been friends for some time — ironically through Sean — but things have developed," an insider told The Sun.
The duo are reportedly to have been spotted getting close after attending separate film premieres.
"Brad came over to Chateau afterwards, changed his outfit and joined Charlize in a corner of the bar," the source has said. “She was on a vodka cocktail while he stuck to mineral water."
“They were ridiculously touchy-feely and his arm was around her back. At one point he winked at her."
“Brad seemed in a really good place — they both looked really happy.”
Pitt has spent the last two years caught up in messy divorce proceedings, and it was recently revealed his mum blames Jolie for ruining her son's life.
A spokesperson for the actor denied to comment.