The Davina McCall gameshow, which aired between 10pm and 11pm, had a total audience of 2.711 million when viewers to Channel 4 +1 were taken into account.
It beat its previous high of 2.067 million on Wednesday, when it was also watched by another 221,000 viewers on Channel 4+1.
The second series of the show had begun on Monday with 1.781 million viewers and another 101,000 on Channel 4 +1.
Channel 4's quiz beat ITV1's News at Ten, which averaged 1.8 million, an 8.8% share, between 10pm and 10.35pm, and the first episode of BBC2's The Stephen K Amos Show, which began with 1 million viewers, 5.1% of the audience.
The slot was won by BBC1's BBC News, which had 4.7 million viewers, a 23% share, between 10pm and 10.35pm.
Channel 5's Law & Order: Special Victims Unit had 1.2 million viewers, a 6.2% share.
Million Pound Drop
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