The Celebrity Traitors semi-final pulled in the biggest peak audience of the series, drawing 10.7 million viewers.
An average of 10.3 million people watched the penultimate episode of the reality gameshow, with a 62% share, according to the BBC.
Thursday night's episode saw comedian James Acaster, 41, admit to his fellow players during the roundtable that he was a traitor following significant scrutiny from actor Michael Sheen. He was subsequently banished from the castle.
The BBC One programme has proved a ratings winner for the broadcaster.
Its second series premiered at the start of October and delivered the most watched debut episode of any series of the programme in the UK, averaging 8.9 million viewers and peaking at 9.1 million. During that episode, actor Richard E Grant shockingly admitted to his fellow players that he had been selected as a traitor before attempting to backtrack.
His efforts to convince the other contestants that it was a joke failed as he was the first player to be banished at the roundtable.
That launch built on the success of the first series of the celebrity spin-off, which debuted last autumn with an overnight audience of 6.1 million, according to the BBC.
The nail-biting finale of that first celebrity run hit a peak of 15.4 million viewers, the biggest TV audience of 2025, with Alan Carr winning as a traitor after successfully tricking Nick Mohammed and David Olusoga into believing he was a faithful.
The civilian edition of The Traitors, which launched in 2022, has also been highly successful.
Its recent series premiere in January brought in an overnight audience of 6.4 million. The finale of that version became the most watched in its history, with a peak audience of 9.6 million.
Hosted by Claudia Winkleman, the show sees 21 celebrity contestants try to seek out the traitors among them who “kill off” players in the middle of the night.
The final will now air on BBC One at 8pm on Friday, with seven players still in the running for victory including traitors Maya Jama and King Kenny.
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