The contestants were awaiting the results of a triple eviction during the live show when the incident happened.
And as the suspense mounted, Ashley James suddenly screamed: “Oh my god someone is trying to get in!” while Jess Impiazzi pleaded: “Oh my god help me I’m scared!”
A shaken Wayne Sleep then shouted: “Big Brother there are people in the house!”
The living room shutters were lowered following the disturbance, blocking the contestant’s view of the garden.
Wayne later clarified: “They’re outside the house, they’re not in the house. They’re in the garden.”
The drama came as comedian Daniel O’Reilly had been given just 30 seconds to say goodbye to his fellow housemates, before being evicted from the Channel 5 show.
And, as the Dapper Laughs star made his way up the stairs, Jess was heard asking: “Did people just come into the house?”
Later in the live show, Emma Willis told concerned viewers: “Everybody’s fine. They didn’t get into the house, everything is under control.”
In a clip shared on Snapchat, Youtubers Ally Law and Ryan Taylor were pictured in the compounds garden.
With one half of the duo donning a head camera and yellow fluorescent jacket, they peered through the glass doors.
Meanwhile, the other told the camera: “What, you didn’t think we’d do it again?”
The break-in came just five days after the pranksters first stormed the Borehamwood compound.
Last Saturday, the duo had recorded Daniel, Jonny Mitchell, Genuine, Ashley and Ann Widdecombe chatting in the living room.
Ally and Ryan, who were spotted with a bright orange jacket suggesting they may have disguised themselves as on-set workers, are well-known for their break-in stunts.
Express.co.uk has contacted a representative for Celebrity Big Brother asking for comment.
Celebrity Big Brother 2018 continues tonight on Channel 5 at 10pm.
