Ashton Kutcher joins 'Two and a Half Men.' Will the show do better or worse?

The announcement Friday that Ashton Kutcher will join the cast of the hit comedy “Two and a Half Men” ends speculation that CBS and Warner Bros. might let the TV show die, after its principal actor, Charlie Sheen, was fired in March.

But it is unlikely, many observers say, that Mr. Kutcher take over Mr. Sheen’s character on the show. Rather, Kutcher’s presence will give the writers a chance to go in new directions.

“Sheen’s character was getting a little thin,” says Robert Thompson, founder of the Bleier Center for Television and Popular Culture at Syracuse University in New York. “As good as Charlie Sheen was, his TV alter ego, Charlie Harper, had begun to wear out. You can only do so many stories with a drinking, drugged-out womanizer.”

The change in the central character raises the question: Will “Two and a Half Men” be as successful going forward? Over eight seasons, the show has enjoyed strong ratings and has been a “tent pole” commodity, meaning it has helped attract other talent and series to the CBS lineup.

A look at TV history suggests that “Two and a Half Men” could go either way. “8 Simple Rules” did not recover well from the sudden death of John Ritter in 2003. But after wide speculation that “Cheers” would fade with the exit of Shelley Long in 1987, the show did even better when Kirstie Alley came on the show. Similarly, when David Caruso left “NYPD Blue” in 1994, critics were worried the show would suffer. It didn’t.

Sheen himself helped extend the hit show “Spin City” when he replaced its Golden Globe-winning star, Michael J. Fox, in 2000.

“The ultimately interesting point in all this is debated in television and theater classes across America all the time,” says Fordham University communications professor Paul Levinson, author of “New New Media.” “Is it the overall characters or the overall story that is most compelling to audiences?”

Commenting on “Two and a Half Men,” he adds, “If Ashton Kutcher succeeds in the absence of Sheen, it will weigh in on the side that characters are less important than the overall story. If he doesn’t succeed, it will be evidence that overall, characters are more important.”

But others argue that a TV show has so many dynamics – writing, characters, star power, chemistry, guest stars, and duration – that it is extremely difficult to sort out the variables.

Already, however, a number of analysts say that “Two and a Half Men” will do better with Kutcher because of the writing and supporting cast.

“Everyone is underestimating how much American audiences love this entire cast coming into our living rooms,” says Gwendolyn Foster, professor of film studies at the University of Nebraska, Lincoln. “They would have been incalculably stupid to throw away one of the most popular ensemble casts ever.”

However popular Sheen was, she adds, Kutcher has all the demographic attractions a TV executive could want. “He is popular with old people, young people, middle-aged people, blue state, red state ... it doesn’t matter,” she says. “He has that amazing combination of good looks that women adore and that men don’t find threatening.”

It is not known what CBS will pay Kutcher, although Sheen was the highest-paid actor on TV, earning just under $2 million per episode.

This year, many have become concerned that the real-life Sheen had become too close to his on-screen persona. The termination letter from CBS to Sheen’s lawyer read in part: “For months before the suspension of production, Mr. Sheen’s erratic behavior escalated while his condition deteriorated. His declining condition undermined the production in numerous and significant ways.”

The announcement about Kutcher comes just in time for next week’s all-important “upfronts” in New York, in which networks roll out their new ideas, casts, and shows for the fall so that marketers can buy commercial air time before the television season begins.

Kutcher first gained recognition as Michael Kelso on the hit TV comedy "That 70's Show," which aired for eight seasons. He went on to star in a variety of movies, including “What Happens in Vegas” with Cameron Diaz and the recent “No Strings Attached” with Natalie Portman.

“I can’t wait to get to work with this ridiculously talented ‘2.5’ team and I believe we can fill the stage with laughter that will echo in viewers’ homes,” Kutcher said in a statement.

Kutcher will join Jon Cryer, Angus T. Jones, Holland Taylor, Marin Hinkle, and Conchata Ferrell this summer to work on the ninth season of the show.