Brendan O'Carroll's appearance on Who Do You Think You Are? topped the ratings on Thursday, overnight data reveals.
The Mrs Brown's Boys star's turn on the BBC One ancestry series brought in 5.30 million viewers (25.7%) at 9pm.
Earlier, DIY SOS: The Big Build returned with 4.48m (22.6%) at 8pm, while Motorway Cops brought in 2.34m (20.9%) at 10.35pm.
On BBC Two, live athletics coverage interested 1.32m (7.0%) at 7pm, followed by Natural World with 1.28m (6.2%) at 9pm.
ITV's Tonight: The Food We Eat gathered 2.51m (13.8%) at 7.30pm (139,000/0.7% on +1), while Harbour Lives appealed to 2.16m (10.7%) at 8.30pm. Prom Crazy fascinated 1.51m (7.3%) at 9pm (158k/1.0%).
On Channel 4, Location, Location, Location continued with 1.12m (5.7%) at 8pm (256k/1.2%), followed by Stammer School with 824k (4.0%) at 9pm (150k/1.0%) and First Time Farmers with 525k (3.4%) at 10pm (127k/1.4%).
Channel 5's Burned Alive: Anatomy of a Murder intrigued 663k (3.4%) at 8pm, followed by the latest Celebrity Big Brother with 1.70m (8.3%) at 9pm (196k/1.3%). Suspects concluded with 697k (4.5%) at 10pm.
On BBC Three, Cuckoo amused 532k (3.2%) at 10pm, while Siblings brought in 476k (3.4%) at 10.30pm.
