Supposedly they didn't get along very well on the set but in later interviews had nothing but nice things to say about each other. I wonder.
1) They both demanded top billing so the producers created the cross credit to accommodate them.
2) They had it written into their contracts that they had to have the EXACT SAME number of lines of dialog.
Supposedly William Holden was also trouble because he had been expecting to be the #1 star on the picture.
I like both but Newman more.
shareThey were fine working together. In fact became good friends after making the movie
shareIt was evidently a wary relationship.
McQueen had been way down the supporting actor list in 1956 when Newman was the new young star of "Somebody Up There Likes Me" and McQueen had to work his way up for a decade to become a star equal to Newman.
By 1968, when McQueen had the superhit Bullitt (same year Paul Newman made the weak comedy "The Secret War of Harry Frigg") they were co-equal.
This story is told of McQueen accepting Butch Cassidy and the Sundance Kid. McQueen's agent called Newman's agent, who called Newman:
Agent: McQueen will be in the movie.
Newman: Great.
Agent: But he has one condition.
Newman: What?
Agent: He wants top billing.
Newman: But I was here first(he had already accepted the movie.)
Agent: Well...yes or no?
Newman: NO.
And Robert Redford became a star.
Likely Newman and McQueen stayed wary friends after Towering Inferno. Remember, McQueen was given Newman's young son Scott in a bit role as a fireman in Inferno. When Scott later died of an overdose, McQueen reached out to Newman.
And so forth and so on. But McQueen died young at age 50 in 1980 and any feud was conclusively over.
One more thing:
Around 1969, McQueen and Newman were photographed together -- along with Barbra Streisand and Sidney Poitier -- as the new owners of "First Artists" -- a consortium of top stars banding together for a mini-studio. Soon Dustin Hoffman joined First Artists and some hits did emerge from the group: Poitier had several, McQueen had The Getaway.