LONDON (Reuters) - Have you ever known that horrible feeling when you realize you've sent a message about a surprise party to the one person who wasn't meant to know about it?

Then spare a thought for Prue Leith, a judge on TV show The Great British Bake Off, who has potentially spoilt a surprise for about 9 million people.

Leith apologized on Tuesday after tweeting the name of this season's Bake Off winner hours before the final was scheduled to be aired in Britain, saying she was in Bhutan and had got confused about the time difference between the countries.

The spoiler was swiftly deleted, but not before the name of the victor was all over the Internet, causing consternation among the program's legions of followers.

"I am so sorry to the fans of the show for my mistake this morning. I am in a different time zone and mortified by my error," Leith tweeted.

The spoiler immediately became a talking-point among British social media users.

"I feel like a deflated souffle now," wrote Bry on Twitter.

Leith's blunder was all the more unfortunate because it came during her first season as a Bake Off judge, replacing the revered Mary Berry who quit after the program moved from the BBC to rival broadcaster Channel 4.

"Mary Berry would never have done this," wrote Padraig on Twitter, although others leapt to Leith's defense.

"It's OK Prue, still think you are awesome. Mistakes happen," tweeted Claire.

The Bake Off involves weeks of competition between amateur bakers who are set a series of increasingly tough challenges. One is eliminated every week until the last three battle it out in the final.

Last year, the Bake Off final attracted 16 million viewers, making it the most watched program of the year on British television.

While viewer numbers have dropped since the move to Channel 4, which unlike the BBC has advertising breaks, the show is still considered a ratings success for the smaller broadcaster, attracting some 8.9 million viewers per episode.

(Reporting by Estelle Shirbon, editing by Ed Osmond)