Someone's kidding. Someone has to be kidding.

They're trying to tell us that Anthony Andrews, who played Sebastian Flyte in "Brideshead Revisited," is going to play Nero in "A.D."

They're kidding, right? How could it be that Andrews, who was so memorable as a drunken young denizen of Oxford in the epic series on PBS, is going to play the fat old emperor of Rome in an NBC miniseries?

Is Andrews, the thinking woman's Tom Selleck, really going to play a debauched old man in an American- made television show?

Well, yes.

And no.

Let's sort this all out. First of all, if you're surprised at the casting, so was Andrews.

"I laughed," he said, recalling the day he was asked about the part. "I, like everyone else, seemed to suffer from a conventional notion of the character -- probably the Peter Ustinov image, a rotund and vicious man."

But when Andrews read contemporary descriptions of the emperor, he found another man. "He was actually frail and spindly, with a slight pot belly -- all the Romans seemed to be that way because of the way they ate -- with blond, curly hair and with a strangely high-pitched and hoarse voice.

"Without a doubt he was an artist in his soul," said Andrews, a man who wanted to redo Rome with artistic values in mind. "But he was unfit to govern, and he was a vicious man.

"He became a debauched figure -- drinking, over-eating and whoring -- going from the figure I discovered to an overweight, debauched character. We pick him up at age 19. He died at 37. My death scene," Andrews mourned, "bit the dust" of the cutting room floor.

So yes, Andrews plays Nero in the series, starting tonight at 8 and running through Thursday.

But no, he doesn't play the same character that Ustinov made us loathe in "Quo Vadis."

"Over time, there's change and development in the character," said Andrews. "He's an extraordinary Gemini character. That's what attracted me to him."

Was Nero really a Gemini? "Let's look him up in the encyclopedia," said Andrews. "Let's see, he was born on Dec. 15." Sagittarius.

Andrews is a Capricorn. He was born Jan. 12, 37 years ago in North London, son of a dancer/mother and a musician/father. He made his acting debut playing the white rabbit in "Alice in Wonderland." He abandoned school at 17 and got a major break when he won a part in the London stage production of "Forty Years On" with John Gielgud.

He is married and has a son 12 and a daughter 10. His wife, whose career is in the fashion industry, directs a London store.

Andrews captured the attention of the PBS television audience in 1982 and held it for nearly three months in "Brideshead." Since then, he has done "The Scarlet Pimpernel" for CBS, a feature film, "Under the Volcano," with Albert Finney and Jacqueline Bisset, and several productions for the BBC.

Who better, then, to ask about the relative merits of American and British television. How do "Brideshead" and "A.D." look side-by-side?

"I think it's difficult to compare them," he said. "They're different pieces. 'Brideshead' couldn't be made in America. It's a specifically British subject matter that only could be done in Britain.

"On the other hand, I don't think you could do some of the American series in England," he said, naming "Hill Street Blues" and "Call to Glory" as his favorite regular programs. Told that "Glory" had been called off the air, Andrews was surprised. "Really? That's a disappointment. It seemed typical of the best of American television."

"A.D.," which depicts 40 years of hostility between the early Christians and the repressive Romans, falls somewhere between the usual American series television and "Brideshead," he said.

"It took two years to make it," said Andrews, "and Brideshead did too. There were enormous problems . . . in keeping everybody happy." But the sets were different matters. A replica of the Roman Forum had to be built for "A.D." It took six months for more than 250 workers under production designer Enzo Bulgarelli (previous credits: "The Agony and the Ecstasy," "Cleopatra" and "Masada") to build a six-block replica of the Forum.

No such problem in making "Brideshead," observed Andrews. All they had to do was point the camera -- the show's main set, Castle Howard, had been there eons.

Probably more important than the nuts and bolts and tunics and columns of production is the emergence of the miniseries as a TV staple.

"I think the miniseries is here to stay," said Andrews. "It's become an international format. We get most American series in Britain and ours are exported to America. There's a merger going on -- I think they're becoming closer in subjects and in how they're shot.

"We shot 'Brideshead' in 16 millimeter, which made things very portable (because of the lighter equipment) . . . You could be set up one place and switch to another if it rained . . .

"Now we shoot in 35 millimeter, making them more exportable," said Andrews, noting that many technically oriented viewers were surprised to find "Brideshead" had been shot in 16 rather than 35 millimeter, with its generally superior look.

Another difference is the higher production costs in the United States. "Budgets make it more expensive to shoot in America," he said, "making speed a necessity. You really need to have your wits about you when you work on an American production."

The miniseries is also merging casts and crews. The "A.D." cast is indeed a potpourri, including Neil Dickson (Valerius), Philip Sayer (Paul) and Cecil Humphreys (Caleb) in roles woven through the entire 12 hours; the players also include Ava Gardner, John Houseman, Richard Kiley, James Mason in his final screen appearance, Jennifer ("Cover Up") O'Neill, Susan Sarandon, Millie Perkins, Fernando Rey, Richard Roundtree, Ben Vereen, Jack Warden, Michael Wilding, Anthony Zerbe.

The series was produced by Vincenzo Labella ("Moses the Lawgiver," "Jesus of Nazareth" and "Marco Polo"), who was born in Rome and is a citizen of the Vatican; the line producer and editor was John A. Martinelli from Los Angeles; Anthony Burgess, an Englishman who wrote the story with Labella, also wrote "A Clockwork Orange," "Jesus of Nazareth" and "Moses the Lawgiver," as well as the aboriginal language spoken in "Quest for Fire."

The designer of 4,500 costumes for "A.D" is Enrico Sabbatini, an Italian, who won an Emmy for "Marco Polo"; he shopped in India, just as the ancient Romans often did, and came back with 92,000 feet of cotton and 102,000 feet of silk. The director of it all is Stuart Cooper, winner of the Slver Bear at the Berlin Film Festival for "Little Malcolm" and "Overlord." Cooper started out as an actor and was one of the "Dirty Dozen." He's from Hoboken, N.J.

"You have to remember that 'A.D.' was truly an international series," said Andrews. "It reflects what's happening."