Comedian Hardeep Singh Kohli, journalist Rosie Boycott and former tennis star Annabel Croft were among five well-known faces who chose to be 'Famous, Rich and Homeless'.
The first of two parts (the second is tonight) earned an audience share of 22.3%, coming in substantially ahead of ITV1's conclusion of a documentary about Britons living in Spain coping with the recession.
'Spain: Paradise Lost' managed 3.6m viewers and a 16.9% share at 9pm-10pm.
'Big Brother', which Channel 4 put into the same slot last night, brought in 1.8m viewers for an 8.3% share. An extra show at 10.55pm-11.30pm earned a 13.6% share as 1.6m tuned in to see the housemates forced to make surprise live nominations for eviction.
On Channel 4+1 the first show notched up 271,000 viewers and the second 97,000.
Back at 9pm-10pm BBC Two managed 1.5m viewers and accounted for a 6.8% share with 'NASA: Triumph and Tragedy', a documentary looking at the preparations in the 1960s for putting the first man on the moon.
Five ran spaghetti western 'For a Few Dollars More' at 9pm-11.45pm, pulling in 1.2m viewers and getting a 7.3% share over the slot.
On Sky One original drama 'Martina Cole's The Take', which last week debuted to an audience of 648,000, was watched by 479,000 at 9-10pm, a 2.2% share.