SIZE mattered very much to Steve McQueen, says his longtime buddy Robert Vaughn.

On location in Mexico with Yul Brynner for "The Magnificent Seven," Vaughn recalls how McQueen asked him, "Did you see the size of Yul's horse?" and fretted about the height of his own mount.

"I pointed out to Steve -- I had seen him around town for years skulking and glowering in casting offices -- that my own horse, which was named Jumbo, was even bigger than Brynner's, but Steve was really angry," Vaughn says.

"And he wasn't happy that Brynner had this big white gun that caught the sun. Steve was trying to outdo the King," -- Brynner had won the Best Actor Oscar for "The King and I" the previous year -- "and, in that, he brilliantly succeeded."

Vaughn, perhaps best remembered for his '60s TV series "The Man From U.N.C.L.E.," will introduce a showing of "The Magnificent Seven" Saturday at 12:30 p.m. at Lincoln Center's Walter Reade Theater.

It's part of a 12-film McQueen retrospective running through Tuesday that includes two other movies Vaughn made with McQueen, who died in 1980: the classic thriller "Bullitt" and the all-star disaster epic "The Towering Inferno."

McQueen was close friends with Vaughn and had sent for his pal to play an ambitious politician opposite McQueen's detective in "Bullitt."

"The script didn't make any sense at all to me, and I thought it was going to be a flop -- just like I did with 'The Magnificent Seven,' where they didn't even have a completed script when they started shooting and they just handed out new pages every day," Vaughn says. "But then I was offered more money than I've ever gotten for a movie, and the plot of 'Bullitt' suddenly became very clear to me."

McQueen's quirkiness manifested itself when Vaughn chose to place a Phi Beta Kappa key on his character's vest.

"Steve came over and objected 'because I wore it in the movie with Faye Dunaway' -- 'The Thomas Crown Affair' -- and I replied, 'Steve, if people are looking at my key and connecting it to Dunaway, something's wrong with the picture.' That satisfied him."

On "The Towering Inferno," McQueen was obsessed with his rival and co-star Paul Newman, making sure they each had exactly the same number of lines.

"Steve never believed he was a good actor," says Vaughn. "Paul was a very articulate actor who wanted to talk through scenes, which was something Steve never did," Vaughn says. "Steve was very hip to the fact that his stardom was based largely on the look he had."

By LOU LUMENICK

Info at filmlinc.com.

More from Vaughn at blogs.nypost.com/movies

Source: NYPost