IF THE United States falls in love with me on Tuesday and files for divorce on Thursday, my life will continue," said actress Pamela Bellwood, whose TV series "W.E.B." premieres on NCB next month. But Bellwood admitted that, failed marriage or no, the prime-time exposure of that big Wednesday is bound to help her career. And Loni Anderson, who has her first regular series role in "WKRP in Cincinnati" (produced by Mary Tyler Moore Productions for CBS), agrees that "Even if the show is only on for six weeks, it makes a difference to your career."

With the Nielsen votes still weeks away, Bellwood, Anderson and some other actresses in new series have been feted by the networks, primed by publicists and previewed for the press, sponsors and network affiliates. Scripts for other TV projects, poster deals and movie offers started coming their way even before the series went into full production. Their hired representatives have been busy turning down TV commercials, modeling assignments and even Playboy magazine layouts.

"The businessmen and agents approach you and say, "We have some packages all worked up for you," said model Pat Klous, who co-stars in CBS' "Flying High."

"There will probably be a poster of the three of us as stewardesses because that's part of the contract," Klous said, adding that she's put a moratorium on modeling until after the series is finished. "Then my price will go up. Pretty smart, huh?"

"I just did the 'WKRP' pilot for the money and because I thought it would be nice to work for MTM," said a wide-eyed Anderson. "But it sold! Now all of a sudden I'm getting bigger offers, films that conflicts with the series shooting schedule so I can't get into them."

Her new status, Anderson said, means she won't have to do any more dumb blond roles: "Three scenes, six lines, one scene always in a bikini. My first job was playig Miss Texas in a beauty contest on 'S.W.A.T.,'" she said. "I thought they cast me because I can do dialects. Instead I found that they hired me because Miss Texas had big boobs, which were talked about during the entire show.

"I have a wonderful dumb blond voice that I don't do anymore. I did it on a 'Love Boat' with Steve Allen once. He took me aside and said, 'Watch out, you do that too well.' I said thank you."

As Anderson spoke, the interview was interrupted by a gentleman in a dark suit. Approaching her table in a dim corner of the Polo Lounge, the man gave her a business card and introduced himself as "from the poster people."

Later, Anderson said that she probably will do a poster "for the money and for the kick of looking back when I'm 40 and saying, 'Hey, I did that and I looked pretty good.'"

Having been readied for TV stardom twice before, wtih co-starring roles in "Blansky's Beauties" and "The Betty White Show," Caren Kaye said that she is not intimidated by the hoopla surrounding her new starring role in NBC's "Who's Watching the Kids?"

"There's no reason it should be scary," she said. "You have to look at it like a game plan. But you have to be careful because people will soft-soap you and tell you can do anything."

But kaye admitted that she fell for the line from pro Arts, the poster company that produced the famous Farrah Fawcett-Majors pinup. "I was flattered that they thought I was pretty enough to sell posters," she explained.

"It's very chic to pull down TV," Kaye said. "But I don't because it has given me exposure I wouldn't have had otherwise. Right now I have a 13-week running commercial for myself."

As evidence of her new clout, Kaye held up a thick envelope containing a movie script, she said, part of a two-picture deal she has with a major studio. "And I want to produce," she announced.

Unlike Anderson and Kaye, Pam Dawber had no TV credits prior to landing a leading role in "Mork and Mindy." The new ABC series is scheduled to air Sept. 11, just a few days before the premiere of Robert Altman's "A Wedding," in which she makes her motion picture debut.

"Isn't it amazing!" Dawber said, that the prime-time TV exposure may do more to promote her career time than the Altman film. "The whole TV stardom thing confuses me because I can't understand why so many people are stars who haven't done anything to deserve it."

A multiple-octave soprano who began performing in stock musicals as a teen-ager, Dawber financed years of acting and voice lessons in New York with a lucrative TV and catalogue modeling career, Altman signed her for "A Wedding" after he saw her first Equity performance, as Jennie in "Sweet Adeline."

"I was leery about getting involved in TV in the first place," she said. "But I'm happy about 'Mork and Mindy' because, supposedly, we're going to try to make a lot of social commentary, about how we are messing up in our society."

Acknowledging that she had not yet seen a script for the show, Dawber said, "Of course, they the network could say, 'Let's cool it with the social commentary and just make it pure entertainment, I know we're basically dealing with a situation comedy, but I hope there's something there, some essence.

"I guess my biggest fear is that the show would be considered trite and stupid. I would feel so awful to be involved in that. I don't mean to cut TV. Well I do and I don't."

Connie Sellecca, Pat Kous' co-star (with Kathie Witt) was more subdued than any of the other new celebrities. "Right now I'm just taking it one thing at a time. I'm working toward the hiatus. The first day of shooting is one day closer to the day of cancellation," she said. "That's not optimistic, but it's realistic, I think."