Steve Carell (right) plays the boss in the US version of The Office

NBC executives are keeping faith in the remake, which has had unspectacular ratings since launching in March.

NBC "could not face the prospect" of axing the show, it said. It hopes The Office will be the next Seinfeld, which also struggled in its first series.

Ricky Gervais, who created and starred in the British original, said he was "absolutely thrilled".

"This is a tale with a moral," he said.

"They could have panicked and sold out to secure success, watered it down into catchphrase comedy with gurning and funny outfits, aimed at the witless and their children.

Ricky Gervais created and starred in the award-winning BBC original

"But they didn't and they've been rewarded. And that sort of thing is twice as satisfying.

"The president of NBC wanted to buy me a sports car after the first episode got 12 million viewers, I said 'no'. Now he can buy me a jet."

The sitcom, which stars Steve Carell in Gervais' role as an incompetent manager, has settled down with about 5.4 million viewers a week, according to the Los Angeles Times.

Friends spin-off Joey is also returning, although NBC entertainment president Kevin Reilly said it had been "a mixed bag to say the least this year creatively".

"I have never felt the show was broken. I felt the show was uninspired at times," he said.

A new series of The Apprentice will see Martha Stewart take Donald Trump's place picking a new business protege.

The lifestyle guru is currently under house arrest after serving five months in jail for her role in a share scandal.