It was the glitzy, record-breaking show that launched some of the brightest entertainment careers in recent times, but as "American Idol" kicks off for a final season Wednesday, it is a star on the wane.

When the 15th series debuts on Fox it will rely in part on a cameo role from rap superstar Kanye West going through the motions of an audition to pull in the punters.

Tough competition, declining appetite among millennials for live television and a new trend of signing a record deal after being discovered on YouTube means that the public has lost its taste for "American Idol."

When the last winner of the franchise is crowned in April, it will be the end of what its magnetic host Ryan Seacrest optimistically calls "part of Americana" and "part of American history."

A spin-off of popular British series "Pop Idol," "American Idol" began in 2002 and pulled in record audiences between 2003 and 2011, culminating in average viewing figures of 31.2 million in its 2005-06 heyday.

The format was simple: thousands of aspiring singers dreaming of stardom audition before a panel of celebrity judges, then fight to keep their places each week in a sing-off decided by a public vote.

TV talent shows date back to the mid-20th century. What was different was the promise of a recording contract and a new life of stardom.

"We had talent shows as far back as the late 40s and early 50s," says Dominic Caristi, professor of telecommunications at Ball State University.

"Talent competitions are not new. But what was new here, the show reinvigorated this idea that people could become a star."

The first winner was Kelly Clarkson in 2002, a 20-year-old cocktail waitress from Texas at the time who went on to sell more than 10 million albums and win three Grammy Awards.

Carrie Underwood won season four in 2005, since selling nearly 60 million albums, and Jennifer Hudson, booted off the third season, went on to win an Oscar and a Grammy as a singer and actress.

"We genuinely create superstars," said Simon Fuller, the British creator, in a clip ahead of the final season. "That's the thing about American Idol that sets us apart."


Losing interest

Part of the show's success was thanks to the charm of Seacrest and the icy putdowns of British impresario Simon Cowell, the most famous of its judges, who stepped down in 2010.

Cowell, dressed in a white shirt unbuttoned halfway to the navel, captured the imagination of an American public reared on political correctness.

"I think it changed, certainly network television in America. Shows like 'Survivor' and 'American Idol' set the tone for reality shows we're watching today," said Caristi.

But over the last 10 years the rise of the Internet and online consumption of music and videos have seen "American Idol" lose its grip.

"Young people who want to be rock stars now have this hope of making a video, submit it somewhere, get attention and become stars," said Caristi.

Justin Bieber and Lana Del Rey are among those who have been discovered in the last 10 years after self-promoting their music on YouTube.

In 2011, rival network NBC launched "The Voice," which in 2013-14 pulled in more viewers than "American Idol."

But more profoundly, the TV talent show came unstuck by the declining appetite among young people for live television, with the preference now for recorded programs they can watch whenever they like.

"More people are watching at whatever time suits them. And so it's harder to get 'buzz' from social media," said Caristi.

To go out with a bang, Fox has promised surprises for the 15th season.

On Wednesday night, viewers will see West, Kim Kardashian's husband, put through his paces at an audition under the watchful eye of judges Keith Urban, Harry Connick Jr and Jennifer Lopez.

Other celebrity appearances are also in the works, stars hoping to cash in from being on television and watched by an audience which is today no more than a third of the record viewership in 2006.