TOM CRUISE and BRAD PITT are set to star together for the first time since “Interview with the Vampire” 20 years ago – and sources say to expect an epic clash of egos!

“Both these guys are used to being top dogs, and when you get them in the same movie, there’s bound to be trouble,” declared a showbiz insider.

“Everyone’s going to be battling constantly to make sure neither of them feels slighted.”

The new film, “Go Like Hell,” will feature Cruise as the late American muscle car designer Carroll Shelby. It will tell the story of the intense racing rivalry be­tween Ford and the Italian Ferrari team – climaxing at the 1966 Le Mans 24-hour endurance race, which an American car won for the first time.

But then dramatic tension in the movie may pale to that off-screen because Pitt and Cruise have plenty of leftover animosity from shooting “Vampire” in 1994, say sources. In a brutally candid interview, Pitt admitted he “hated” doing that film, adding that he didn’t like Tom.

“He bugged me,” Brad reportedly declared at the time. “There came a point during filming when I started really resenting him. He’s North Pole, I’m South. He’s always coming at you with a handshake, where I may bump into you. There was this under­lying competition that got in the way of any real conversation.”

On the set, 5-foot-7 Tom literally tried to rise to Pitt’s stature – wearing boots that added about two inches to bring him closer to Brad’s 6-foot height.

In 2009, outspoken Brad again got under Tom’s skin while promoting his action flick “Inglourious Basterds.” He dissed Tom’s box-office flop “Valkyrie,” slamming it as “a ridiculous movie.” The next year, the ill will between Brad and Tom threatened to explode when Angelina Jolie got the plum role of a CIA agent-turned-spy in “Salt.” Tom lost the part, which was originally written for a man, by reportedly haggling over salary and control of the movie.

“Tom really wanted that part and was not pleased they changed the character to a female,” said a pal.

When Brad heard that Tom was grousing about what happened, he started snidely referring to him as “Dr. Strange,” revealed the source.

But now, despite their past history, Brad, 50, appears ready to work with 51-year-old Tom again in “Go Like Hell.”

“Brad’s been sent the script, and it’s got to be up to his standards,” said the insider. “He put his recent hit flick ‘World War Z’ through rewrite after rewrite, generating bad press before the movie even opened.”

Meanwhile, Tom has had his own problems – in­cluding recent clunkers “Jack Reacher,” “Rock of Ages” and “Knight and Day.”

Said the insider: “I think Tom’s dying to step in the ring with Brad and prove he’s still ‘Top Gun.’”