A source tells Us Weekly the actress and director have taken their relationship to the next level. The pair share a long history of creative collaboration, with Thurman having starred in three Tarantino films.
The person reports the two shared a villa together in Cannes, and spent personal time together in addition to their public appearances at the film festival.
"They had a thing and got together again recently," the source says. "He's loved her for years."
"There has always been an attraction," another source adds. "She has indulged from time to time, and that's how their relationship has always worked."
"They talk often," the person continues. "They go out to lunch in NYC when he's around. He always tries to find a role for her, or have her involved somehow."
Thurman recently split from fiancé Arpad Busson for the second time in April. She was previously married to Ethan Hawke, and has a daughter and son with the actor.
The actress and director will soon reunite on a professional level for Kill Bill: Vol. 3.