Thousands of fans stampede through police barriers after camping on the street overnight.
Ambulances were called as many fainted and needed medics.
Kim, Kourtney and Khloe Kardashian have only a limited amount of time in the UK, and their fans are well aware of this.
With that in mind, Westfield London Shopping Centre was overrun with crazed Kardashian fans eager to meet and greet their idols on Saturday morning.
Police and security guards struggled to control crowds of teenagers surging through the gates to see the sisters who were attempting to launch their Kardashian Kollection.
Army of Kim-bots:
Kim, 32, was wrapped warm for the promotional activity as she emerged from her hotel in the morning wearing a thick fur cape.
The reality TV star is used to being the centre of attention but even she would have been surprised at the response of her cross Atlantic followers.
Khloe, 28, had only arrived in the capital on Friday but got straight into the thick of things by joining her two sisters for the launch.
The X Factor USA host was concerned, however, about the huge amount of people that had turned up and especially the large number people who had camped over night.
Khloe said: 'We’ve already had such an amazing response to our signing at Westfield London today and are so excited to see everyone!
'We can’t believe how many incredible fans are waiting outside (several thousand!) In order to keep everyone safe, Westfield had to action a contingency plan for those who stood in line overnight and allowed those people to stay in the car park.'
She continued: 'Anyone not already there is of course still welcome to come out today, but I wanted to send a personal message to make sure everyone stays safe!'
Once the girls took to the stage promptly at 12.30pm the shopping centre erupted with cheers and screams as the crowds went wild.
While Kim wore a predictably tight black dress with a gold belt, it was Khloe who looked the most fashionable.
The celebrity couple arrived at the club in two Rolls Royce Ghost Phantoms and partied with other VIPs for over an hour.
Kim even bought a round of Midori shots for her newly acquainted friends and gave them some Ace of Spades champagne.
To top the night off, she showed that she is Kanye's biggest fan by dancing away to some of his many chart topping tracks.