'Dallas' Creator David Jacobs on the Moment Larry Hagman Became J.R. Ewing

The first-season cast of Dallas, from left: Duffy, Principal (in red), Charlene Tilton (in blue), Barbara Bel Geddes, Jim Davis, Hagman and Gray.

The actor threw in an unscripted laugh, which "added an 'Oh boy, hold on to your hats! This is going to be fun" moment, the series creator tells THR.

This story first appeared in the Dec. 7 issue of The Hollywood Reporter magazine.

I've heard it said that the role of J.R. Ewing was relatively minor at the beginning of Dallas. But that's not so. J.R. appears on Page 3 of the 1977 pilot script. He drives the main story, and he speaks the last words in his close-up during the last shot. But what Larry did in that final shot showed how he'd taken possession of his character.

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In the pilot, J.R. has tried to trap Pam, Bobby's new wife [played by Victoria Principal], in a compromising situation with ranch foreman Ray [Steve Kanaly]. When his plan fails, J.R. says: "I underestimated her. I won't make that mistake again." And then the script says: "He smiles. Fade Out."

But Larry didn't smile; he laughed. Sounds close -- smile, laugh, almost the same, right? Wrong. The smile meant he appreciated that he'd found a worthy adversary in Pam. The laugh added an "Oh, boy, hold on to your hats! This is going to be fun!" That was J.R. Ewing!

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J.R. was a symbiotic union of actor and character -- bigger than the sum of the two parts. Is the death of Larry Hagman the death of J.R. Ewing? It's hard to think otherwise. Is it the death of Dallas? It doesn't have to be. But whatever the future of Dallas, the long shadow of J.R. will fall over it forever.