Cat with eyebrows is a star online

A cat which looks permanently worried because of his unusual markings is taking the internet by storm.

Sam, a former stray cat from New York, has two black marks on his forehead resembling eyebrows.

His owner, who wishes to remain anonymous, rescued Sam and set-up an online profile dedicated to him and his 'eyebrows'.

Sam now has more than 24,000 followers on picture sharing site Instagram with his anxious expression is earning him worldwide fame.

Since Sam's owner started the Instagram account, the photos have spread to Twitter, Facebook and now his own dedicated website and fan-base.

Sam's biography says the cat enjoys 'eating, worrying, surprises and pooping'.

His owner says some of the proceeds from his website will go to Empty Cages Collective, a non-profit, no-kill, volunteer based animal shelter in Brooklyn.