Patrick Duffy slipped right back into the cowboy boots with no trouble at all for TNT’s 2012 version of Dallas.

Literally.

“I gotta tell you. I was a heartbeat away from playing Bobby Ewing for the last 20 years,’’ he said from his home in Oregon. “Once I put his wardrobe on, it was eerily comfortable. I was ready to go again.’’

Yeehaw! The legendary nighttime soap — which ran from 1978 to 1991 — is back with a mix of old and new at Southfork Ranch.

Also along for the ride are Larry Hagman as oilman/patriarch/villain JR Ewing and Linda Gray, playing the forgiving, suffering ex-wife JR still loves, Sue Ellen.

“We’re the old ponies in the parade,’’ said Duffy, who decided to sign on for this version because it just worked.

“I really think in all honesty that it’s a perfect continuation of the series,’’ he says. “We can track these characters seamlessly — from Bobby celebrating his 60th birthday to JR being in a home. It was a logical extension.’’

Duffy, 63, and his costars had been approached over the years about various Dallas projects, but they were never interesting enough.

“We’d heard so many different permutations, and they all just sucked; no one knew how to write it,’’ he said, adding that the most horrific project was a rumored movie starring John Travolta, Jennifer Lopez and Shirley MacLaine.

“I read the script, and I have to say that’s one of the worst things I’d ever seen. Just awful.’’

So Duffy put the revival idea aside and focused on his calm life in the Pacific Northwest.

“We pretty much assumed it would never get done, as tantalizing as it was.”

What changed his mind? Executive producer Cynthia Cidre’s script. “She got it. She understood the perfect blend of what made this show so iconic in the ’80s,’’ the Montana native said. “We haven’t regretted a page. A paragraph. A day of work.’’

As for the new generation, Duffy had never met anyone but did his research.

“Thank God for the Internet. I imdb’ed everybody,’’ he said, referring to the International Movie Database.

Locals may recognize Miami-raised actress Julie Gonzalo, as the love interest of Christopher Ewing, Bobby’s adopted son ( Jesse Metcalfe).

For a show with so many warring characters, everyone got along incredibly well. “We just fit,’’ added Brenda Strong, who plays Bobby’s new wife, Annie. “It’s one of those rare occasions when you really enjoy the people. There is a real chemistry and a generosity.’’

Strong had just finished up Desperate Housewives when Dallas started filming. “What a constellation of emotions. I was sad yet happy at the exactly same time.”

Jordana Brewster of the Fast and the Furious films plays Elena, the sexy daughter of the Ewings’ cook. At 32, she was just a kid when Dallas was in its heyday.

“I knew about the whole ‘Who Shot JR?’ slogan and the theme song and everything, but once I got the job, I watched all the episodes. It’s addicting,” said Brewster, who would be totally up for another season. “We all became good friends. They have to keep separating us in the hallways!’’

Duffy wouldn’t be averse, either.

“Back 30 years ago, we had magic casting, and no one knows how it happens,” he said. We’re reliving that circumstance again. The first season was the most enjoyable work so far for me. I’m looking forward to how much more we can squeeze out of this old horse.”

Dallas premieres at 9 p.m. Wednesday on TNT.