Unearthed footage from Big Brother USA has shown the harrowing moment the housemates are told about the 9/11 attack.
When terrorists flew two planes into the World Trade Center on 11 September, 2001 it felt like the whole world was watching.
In the US only a scant few people were cut off from sources of news that would have kept them in the loop about the attack.
A handful of those people were housemates on the second series of Big Brother USA, as due to the show's rules they weren't allowed contact with the outside world.
However, it was decided that the show's rule on a full news blackout should be broken in the extraordinary circumstances, particularly as a cousin of housemate Monica Bailey was listed as missing after the attack.
Monica, along with fellow housemates Will Kirby and Nicole Nilson, were told the basic information on what had happened on the day of the attack, but the trio didn't get a full and detailed lowdown until the series finale on 20 September.
Producers made the decision to alert the trio about the attack after Monica's sister called them to make them aware of her missing cousin.
In the video the three housemates are told that the twin towers had been hit by 'hijacked commercial airliners', informing them that 'people were evacuated' and informing the three that they'd been in contact with their families.
They then went on to reassure Monica that her sister and niece were 'fine' before explaining that her cousin who worked at the World Trade Center had been missing.
Monica was told her family was waiting to hear more information and reassured that at this point being missing 'doesn't mean anything bad'.
It was also decided not to show footage of the disaster to the housemates as that would have meant installing a TV, with executive producer Arnold Shapiro telling Entertainment Weekly 'no one inside asked for that'.
Shapiro explained that Monica did not ask to leave the Big Brother house after hearing about 9/11 and turned down an offer to speak with her sister as 'it would probably unnerve her'.
The producer went on to say the trio 'thanked us' for the way they handled breaking the news of the terrorist attack to them.
Monica's cousin Tamitha Freeman worked at the World Trade Center and was missing at the time the housemates received the news about 9/11.
She was later declared to have died in the terrorist attack.
If you have experienced a bereavement and would like to speak with someone in confidence contact Cruse Bereavement Care via their national helpline on 0808 808 1677