The third episode of The Celebrity Traitors drew a peak audience of 10.3 million as viewers watched Richard E Grant banished from the castle.
It was the most watched episode of the series so far, the BBC said, with an average of 10 million viewers and a 60.4% audience share.
The opening episode peaked with 9.1 million people and averaged 8.9 million, while the second peaked at 8.6 million with an average of 8.5 million.
Grant's exit came in Thursday's episode, after he slipped up and said he was a traitor mere moments after being chosen.
The actor received the majority of votes from the other contestants, including from both of his fellow traitors, Maya Jama and James Acaster.
As Grant stood in front of the players to reveal his identity, he said: “I am… an unfaithful traitor.”
Speaking to the camera, he said: “I have been annihilated. I have managed to checkmate myself, which, as far as I’m aware, has never been done.”
Rather than murder, Jama and Acaster chose to seduce mathematician Hannah Fry and make her the third traitor. The professor accepted their offer to join following the roundtable.
Later in the episode, actress Myha'la received the majority of votes from her fellow celebrities and was banished from the castle.
In her speech, she said: “I have loved getting to know you all, thank you for loving me.
“I will say to the faithfuls, I don't think the traitors are as dumb or silly or confused as you might think they are. I think they are a lot smarter.”
The show ended on a cliffhanger as Fry, Acaster and Jama shortlisted Bella Ramsey, James Blunt and Sebastian Croft for murder.
The fourth episode of Celebrity Traitors airs on Friday at 8pm on BBC One.