Filming for Celebrity Traitors has kicked off, with the star-studded cast descending on Ardross Castle in the Scottish Highlands. Production on the much-anticipated spin-off got underway this week, with the celebrities set to put their detective skills to the test as they attempt to root out a group of traitors among them. Several big names have been spotted arriving at Inverness Airport, including Jonathan Ross, Tom Daley, Charlotte Church, Stephen Fry, Alan Carr and David Olusoga. Other high-profile figures set to appear in the new series include Good Morning Britain's Kate Garraway, rugby player Joe Marler, YouTuber Niko Omilana and Line of Duty's Mark Bonnar. The line-up is rounded out by comedians Joe Wilkinson and Lucy Beaumont, presenter Clare Balding, EastEnders star Tameka Empson, and acclaimed actresses Celia Imrie and Ruth Codd, reports OK! To maintain the show's mystery, the BBC has implemented a number of strict rules on set. The Sun reports that the broadcaster has seized the celebrities' phones, with security keeping a close eye to prevent any collusion ahead of filming. Before the cameras started rolling, the stars were kept separate in a hotel, with a source revealing to the publication that there are no special privileges being granted. "The BBC aren't taking any chances with the contestants - even though they're household names. They are all holed up in a hotel together but they are being kept apart with a security guard on their floor at all times to make sure they're not swapping tactics or talking," an insider explained. "In the normal series of The Traitors, the contestants' phones are removed and there have been no special measures put in place for the celebs." The source continued: "Some of them moaned about not having their phone but the BBC need to be sure they're not messaging or communicating on social media - so it's a total ban. Instead the BBC have a production phone for the celebs which they can use to make a phone call home, but a member of staff is never far behind. "The BBC want this series to be as explosive as ever, so they won't allow any collusion." Claudia Winkleman is set to return as the host of the popular programme, which debuted in the UK three years ago. Since then, the format has seen international versions in the US and Australia, featuring personalities such as Chrishell Stause, Dylan Efron, John Bercow and Ekin-Su Cülcüloğlu, who have all tried their hand at the game's strategic deception. Celebrity Traitors will air on BBC One later this year