have reportedly taken their friendship to the next level after working together for many years.
Thurman, who has been a friend and muse to Tarantino for many years, starred in director's films like Pulp Fiction and Kill Bill.
Thurman and Tarantino came close during the Cannes Film Festival where they celebrated the 20th anniversary of Pulp Fiction, reported Us magazine quoting multiple sources.
"They had a thing and got together again recently. He's loved her for years," a source told the magazine.
Pulp Fiction was Thurman's breakout movie and later went on to work with him in Kill Bill: Volumes 1 and 2. "There has always been an attraction. She has indulged from time to time, and that's how their relationship has always worked," another source told the magazine.
Read: Cinema as I knew it is dead: Quentin Tarantino
Thurman was married to Ethan Hawke for six years before divorcing in 2004.
In 2007, Thurman got engaged to hedge-fund magnate Arpad 'Arki' Busson, with whom she shares a 22-month-old daughter Rosalind Arusha Arkadina Altalune Florence Thurman-Busson.
Thurman and Busson ended their tumultuous on again-off again relationship recently.
Tarantino has previously been linked to stars like Kathy Griffin and Mira Sorvino.