Big screen heavyweights George Clooney and Quentin Tarantino have squared off in a bitter war of words — and Hollywood stars are taking sides!

“Quentin started it, and George is vowing to finish it,” an insider exclusively tells In Touch. The rift opened when the Pulp Fiction director was rattling off the some of the actors he considers to be leading movie stars and included Clooney’s BFF Brad Pitt but not him.

That clearly ticked off Clooney. “The [interviewer] goes, ‘Well, what about George?’” says the Ocean’s Eleven hunk. “He goes, ‘He’s not a movie star.’”

Tarantino then took it a step further by snidely asking the interviewer to name one of Clooney’s movies “since the millennium.”

Clooney huffs, “I was like, ‘Since the millennium?’ That’s kind of my whole f–king career!”

The two-time Oscar winner, 63, adds he was “irritated” by Tarantino’s slight, and since then our sources say George’s pals have lined up on his side.

George Clooney vs. Quentin Tarantino! Why Actor Is ‘Furious’ at Director and ‘Demanding an Apology’
Jeff Kravitz/FilmMagic, Inc

“George is furious at Quentin and is demanding an apology,” says the source. “Pitt is standing by him as are Julia Roberts, Rande Gerber and other big names in George’s wide circle of celebrity pals. They all love him.”

Meanwhile, eccentric Tarantino, 61, who costarred with Clooney in the vampire flick From Dusk Till Dawn, doesn’t seem to give a damn! “Quentin is a Hollywood rogue who doesn’t waste his time kissing up to celebrities,” notes the insider. “He’s one of those ‘artistes’ who are all about the craft.”

“But ask him and he’ll hold his ground. He’s clearly not impressed by Gorgeous George!” the insider concludes.