Mark Bonnar has described filming the celebrity edition of BBC reality series Celebrity Traitors as "so intense" and said the show's 19-strong cast have remained in touch via a group WhatsApp chat.
The 56-year-old Scottish actor, who filmed the spin-off at Ardross Castle in the Highlands in April, told The Sunday Times that the production’s isolation — contestants had no phones while inside the castle — made the experience all-consuming and helped forge strong bonds among participants.
Bonnar said he signed up in part because his wife and children are fans of the original series, and he enjoyed mingling with a cast that included well-known names. The celebrity iteration is fronted by Claudia Winkleman and features a wide-ranging lineup that, according to BBC and media reports, includes Stephen Fry, Alan Carr, Tom Daley, Paloma Faith, Jonathan Ross, Clare Balding, Charlotte Church, Kate Garraway, and others.
Stephen Fry, who also appears on the celebrity series, described his own experience on the show as "emotionally violent" in comments on The Show People podcast. Fry likened the experience to "a Chinese foot massage — you know it is absolutely agony but you sort of want to do it again," and said he had been drawn to the programme after watching earlier series.
Production sources and press coverage say filming began in late April, with cast members flown into Inverness Airport and transported to Ardross Castle under measures designed to preserve secrecy. The Sun reported that executives implemented a tight operation, including a temporary no-fly zone over the host site, to reduce the risk of leaks. The celebrity version has already finished shooting, and the BBC is expected to air it in autumn 2025, although a precise broadcast date has not been confirmed.
Journalist Marina Hyde told The Rest Is Entertainment podcast that the celebrity contestants received a flat appearance fee of £40,000 each, a figure she described while comparing pay practices across high-profile shows. Co-host Richard Osman noted the parity in payment, comparing the arrangement to other ensemble celebrity productions.
The format of Celebrity Traitors pits a group of contestants into roles of "Traitors" and "Faithfuls," with social manipulation and betrayal central to the game. Producers have previously described the mechanics as highly psychological; Fry said he was interested in how the show affects participants' behaviour and decision-making.
Alongside Bonnar and Fry, the announced celebrity cast includes comedians Alan Carr, Nick Mohammed, Joe Wilkinson and Lucy Beaumont; actors Celia Imrie, Tameka Empson and Ruth Codd; singers Cat Burns and Paloma Faith; presenter and YouTuber Niko Omilana; former England rugby player Joe Marler; and historian David Olusoga, among others. The series is a celebrity spin-off of the non-celebrity format that previously established the show's premise and production approach.
Bonnar said the cast remain in touch via a WhatsApp group as they await the series’ broadcast, and that the lack of phones during filming left participants focused on the game. Broadcasters and production companies have kept details of the celebrity series tightly controlled in the lead-up to transmission, citing the show’s reliance on secrecy to preserve surprise and dramatic turns.
The BBC has not announced a specific air date or further production details beyond the confirmed host and cast roster. The celebrity edition’s arrival follows the success of earlier seasons of Traitors, which drew significant viewer interest and prompted the network to commission the celebrity special.