By Jill Serjeant

LOS ANGELES (Reuters) - Larry Hagman's conniving Texas oil baron J.R. Ewing helped turn "Dallas" into a worldwide hit more than 30 years ago, and gave television one of its most alluring and dastardly villains.

Hagman, now 80, is putting on his boots, his wicked grin and 10-gallon cowboy hat for a new version of the TV series, starting June 13 on cable channel TNT.

The TV veteran sat down with Reuters recently to talk about returning to the Southfork Ranch, his off-screen passion for alternative energy and his hatred of cowboy boots.

Q: What was your first reaction when this new "Dallas" TV series was pitched to you?

A: "I said, 'who's on the show?' and they said Linda Gray, Patrick Duffy. I said 'done deal' before I even saw the script. We're buddies. It's three musketeers kinda stuff. We like working with each other."

Q: How hard was it to get back into the character of J.R. after all these years?

A: "Honey, it was like coming home. It's no trouble getting into that character. I don't know how much is the character and how much is me anymore."

Q: You gave me a fright in the premiere, with J.R. spending so much time sitting silent in a chair with his eyes closed.

A: "That was just a hook to get me back in and to explain what I've been doing for the past 20 years. I've been in this place, kind of sequestered. Assisted living, I believe they call it. In the old days, they would call it bedlam. Depression - that is how they described it. Anyhow, it gets us going."

Q: How much can you tell us about the plot of the new show? Has J.R. mellowed at all?

A: "I think you will find he is just as big a cad now as he was then."

Q: You told me last year when you were selling memorabilia that you hated cowboy boots because they were so uncomfortable. So how are you managing with having to wear them again?

A: "Wear two sizes too big and don't walk very far. And when you sit down and they are doing close-ups, take them off."

Q: You announced you had cancer just as filming started. How are you doing now?

A: "I'm OK. They gave me a few weeks off in the middle as I'm not heavy in every show. Then I shot a lot at the end. It didn't affect my presence on the show."

Q: Do you think the new "Dallas" will have the same kind of appeal it did 30 years ago?

A: "I sure hope so, otherwise we are wasting our time! No, listen. If it gets half the people watching that we had for the original, we would probably be No. 1 nowadays. With the built-in audience we have left from a couple of generations ago, and the new kids that are really good actors, and good scripts, I think it will be successful. And if it is not, it's fun anyway."

Q: "Dallas" still has a big following abroad. Where are most of your own fans now?

A: "Germany, England, Ireland, France, North Africa, South America, India ... I was amazed to find out that 'Dallas' is very popular in India, so I will have to go over there and do some personal appearances."

Q: Is it true you have been a user of alternative energy long before you started playing a wealthy oil baron on "Dallas"?

A: "I used to have all my cars running on propane, that was about 40 years ago. Then I investigated wind power and sun power and thermal power and stuff like that. I live on the top of a mountain in Ojai, California - about 1,000 meters high. My sun starts at sun-up and goes all day, so I have an ideal place to put solar panels. I have the largest private solar home in America! I manufacture electricity so the electric company has to pay me about $10,000 a year for what I don't use."

(Reporting By Jill Serjeant; Editing by Bob Tourtellotte and Gunna Dickson)