The high cost of Frasier is said to have ruled out a 12th series

The official announcement was made at a press conference involving the show's cast in Los Angeles.

In November the comedy's central star, Grammer, had hinted it might return for a 12th season on NBC.

NBC president Jeff Zucker said: "We are all proud of the fact we'll never put together a cast as brilliant as this."

Reprieve

First broadcast in 1993 as a spin-off from 1980s sitcom Cheers, it was widely reported that the current season of Frasier would be its last.

Rumours of a reprieve were fuelled by its star and Jeff Zucker, who told the Variety website, "the door is still ajar" for the series' return.

But the cost of the Emmy award-winning show prohibited such a move.

"The finances would not have worked for another season," an NBC spokeswoman said.

In 2001 NBC signed a $374 million (�202 million) agreement to renew Frasier, translating as roughly $5.2 million (�2.8 million) per episode.

Kelsey Grammer and co-star David Hyde Pierce were each paid seven-figure salaries to remain in the show until 2004, making Grammer the highest paid US TV actor at the time.

When it ends Frasier will have matched the 11-season run of Cheers.

It means network NBC has to find replacements for two of its most popular programmes - sitcom Friends ends its 10-year run later this year.