Last week, a spot of toothache was the only cloud on Knut's horizon. Now, he's staring in the jaws of death.

But it's the price of fame, as many a stalked celebrity can tell you. Only recently spotted gambolling at the feet of Leonardo DiCaprio on the cover of US Vanity Fair, Knut is now the recipient of sinister death threats.

The mass-circulation Bild daily reported Thursday that the Berlin zoo authorities had received a letter from someone threatening that Knut was about to breathe his last.

Taking matters in their own hands

Police are assuming the culprit is "confused" and said they would not take the threat "too seriously."

What with the recent media circus surrounding Berlin's favorite bear, the police already maintain a daily presence in the zoo, but said Thursday they would not "increase security at (his) cage" merely because of the threat -- the additional officers visitors might have observed on patrol were there on account of a visit from the president of Madagascar.

That wasn't good enough for the zoo authorities, who have now hired 15 private security guards to protect their VIP charge.