The celebrities were awaiting the results of the final housemate to leave on the triple eviction night when two YouTube pranksters, Ryan Taylor and Ally Law, appeared in the garden.
Jess Impiazzi could be heard saying: "Oh my God. Help me, I'm scared," as they realised the pair were in the CBB garden.
The shutters on the windows came down almost immediately as the housemates were in a mix of fear and saying goodbye to Dapper Laughs.
It was between the comedian and Courtney Act who would be the final housemate to leave the house that evening.
The housemates were confused and scared at the break in. Wayne Sleep tried to clarify to Big Brother saying: "Big Brother there are people in the house. They're outside the house, not in the house.
However, once the shutters were closed the housemates all cheered Dapper Laughs as he climbed the stairs.
He was so focused on going home he didn't appear to react to the news that there were two uninvited housemates in the garden at all.
"Everybody is fine, they didn't get into the house, everything is under control," Emma later told the viewers.
It's not the first time the house has been broken into. Last week Ryan wore a high-vis jacket to break in and secretly film the housemates through a glass door in a much more covert operation than this one.
The duo documented the who thing with cameras on their heads, promising to upload a video of the whole ordeal to YouTube later.
They also posted as they were in the house on Snapchat. Ryan said to the camera: "What, you didn't think we'd do it again?" from the CBB garden.