The business mogul, who has acted as an aide to Lord Alan Sugar on the programme since 2009, was shaking in fear during one high-wire moment in an upcoming episode.
Karren, 52, spoke on This Morning ahead of the new series launch, and admitted she got more than she bargained for during one unusual task.
This year, she’ll be starring alongside previous winner Tim Campbell, who is acting as an aide to Lord Sugar in Claude Littner’s place.
Speaking to hosts Dermot O’Leary and Alison Hammond, she said that one episode sees contestants tasked with promoting Europe’s longest and highest zip wire in Wales.
‘We actually do a tourism task for Wales, which involves Europe’s [tallest and longest] zip wire,’ Karren said.
Baroness Brady, Lord Sugar, Tim Campbell MBE return as judges for The Apprentice in 2022 (Picture: BBC/Boundless/Ray Burmiston)
‘I am terrified of heights. I had to go down it. I can tell you I was scared, but not as scared as the candidates, who were screaming their heads off in fear.’
She added:’ It really is a lot of fun this series.’
The Apprentice returns to BBC One this week with 16 ambitious new entrepreneurs battling it out for Lord Alan Sugar’s £250,000 investment in their business.
Each task will end with the candidates being summoned in to fight their corner in the boardroom, with Lord Sugar, Karren and previous winner Tim Campbell watching their every move.
This year’s contestants have been revealed (Picture: BBC/Boundless/Ray Burmiston)
The new recruits have been revealed, with a former rugby player, dessert parlour owner and a pharmacist among the contestants taking part in this year’s series.
Not every is pleased about the show’s return, though. Lord Sugar’s old adversary Piers Morgan was less than impressed with the notion of the returning series.
It comes after The Apprentice star Claude gave fans an update on his health after he was missing from an upcoming promo for the latest series of the BBC show, confirming that is Tim stepping into his place.
The Apprentice returns on Thursday 6 January from 9pm on BBC One and BBC iPlayer.