Charlize Theron and Brad Pitt. Picture: AP/Reuters

South African-born actress Charlize Theron and Brad Pitt are reportedly dating.

According to The Sun, the Hollywood A-list duo have been cosying up for about a month and were recently "all over each other" at a showbiz event.

“They have been casually seeing each other for nearly a month now. They’ve been friends for some time but things have developed,” a source told the publication.

Reports claim that the couple were spotted laying on the PDA last weekend after Pitt, 55, hosted a screening of "If Beale Street Could Talk" and Theron, 43, was a guest of honour at a "Roma" event at Los Angeles' Chateau Marmont.

Their relationship reportedly began over Christmas, after they were introduced by Theron's ex-fiancee, Sean Penn, who she split from in 2015.

Meanwhile, Pitt has been caught in a lengthy divorce from Angelina Jolie following their split in 2016.

Jolie, 43, and Pitt reached a custody agreement in November 2018 after battling one another over their six children for more than two years.