A contestant on the second US version of Big Brother has been thrown out of the house after holding a knife to a fellow housemate's throat.

Bartender Justin was ordered to leave the house following the incident and given a three-hour talk with a psychologist.

The CBS show, which opened a week ago to mediocre ratings, sees 12 strangers living together for the chance to win $500,000 (�355,300).

Bosses promised a more exciting second series

But events turned nasty in the house when 26-year-old Justin was talking and kissing fellow contestant Krista in the kitchen.

Inappropriate

CBS bosses report he was then seen to pull a knife on the 28-year-old waitress, saying "Hang on, I'm going to slash your throat. Would you get mad if I just killed you?"

He later insisted it had been a joke.

But because it was not the first time he had displayed extreme behaviour, producers took the view that he had to go.

Executive Arnold Shapiro said: "We just determined that even though he was telling us that it was his sense of humour and he keeps telling us he's not violent, the fact that he did that is inappropriate behaviour.

"He crossed the line."

Intimidation

Justin had already been warned about derogatory comments made towards women after he got into an argument and admitted using intimidation tactics.

CBS has yet to decide whether to screen the violent incident but it will explain the reasons for his departure on air.

Unlike the UK's version, the first series of Big Brother was not a big ratings pull for American audiences.

The first show of the second series pulled in 8.2 million viewers.

Shapiro dismissed the thought that Justin's eviction would be good for ratings.

He said: "Whether this is good for the ratings or whether this is good for the show, I haven't given a thought to that.

"My mind doesn't work like that. I have a lot of compassion for the other houseguests and for Justin. ...Certainly, I'm not happy about this."