It's been 20 years, but Barbara Eden and Larry Hagman are back together again on a television series.

Oh, the setting and the characters have changed considerably. From 1965-70, the pair starred in "I Dream of Jeannie" as good-guy astronaut Tony Nelson and the genie who loved him.For the next five episodes (beginning Friday at 9 p.m. on Ch. 5), the setting is "Dallas." Hagman, of course, is that man everybody loves to hate, J.R. Ewing, and Eden is a rich, powerful woman out to destroy him.

"I won't be calling him `Master,' that's for sure," Eden said in a telephone interview.

But while the relationship between their characters has changed, the relationship between the actors has not.

"The first time we were together on the set we sort of just stood and looked at each other from across the room," Eden said. "It was kind of strange. We started to hum that theme from `The Twilight Zone.'

"It was just as though nothing had ever stopped. We felt like that's the way it ought to be."

When the producers of "Dallas" called and offered her the part, Eden jumped - and not just for the chance to work with Hagman for the first time in 15 years. (They did a TV movie titled "A Howling in the Woods" back in 1975.)

"I love the character of Lee Ann De La Vega," she said.

A former Texan, De La Vega married a wealthy Venezuelan oilman. Upon his death, she took over the operation of his multibillion-dollar company.

"She's kind of complicated. She's not an out-and-out bad person, but then, of course, bad people never think they are," Eden said.

She may not be bad, but De La Vega has a bad attitude about J.R.

"She's out for revenge," Eden said. "I don't want to give away too much, but she knew J.R. in college, and he did something that wasn't too nice to her.

"He doesn't remember her, but she certainly remembers him."

What "Dallas" fans do know is that brother Bobby is intent on selling J.R.'s beloved Ewing Oil. And De La Vega is interested in buying it.

But not as a business venture. Let's just say that she has definite plans in mind for the company - and for J.R.

CBS, of course, is hoping that the reteaming of Eden and Hagman will revive the flagging ratings of "Dallas." Generations of viewers around the world are familiar with the pair because of "I Dream of Jeannie" reruns.

"Oh my goodness, yes," Eden said about the continuing interest in the series. "It has never been off the air in the past 25 years.

"I guess it has one of the widest ranges of viewers in the world. When I'm in England or France, people stop me on the street to talk about `Jeannie.' I even get letters from places like Russia and Czechoslovakia."

And while Eden hasn't achieved series success to match "Jeannie," she's worked steadily in theater and on TV movies. According to those TVQ ratings that measure an actors recognizability and likability, she's still one of the most popular actresses on television.

So popular that NBC still has plans to build another series around her - although that's still in the planning stages.

But for now, Eden is busy with other projects. And glad she accepted the part on "Dallas."

"It's wonderful to play a rich, powerful, smart woman and match wits with J.R.," Eden said. "I had a great time doing it.

"Of course, Larry is great. I've loved watching him do all those terrible things as J.R. Now I get to do terrible things too."