Kate Garraway’s documentary about her husband Derek Draper’s Covid-19 ordeal attracted 4.5 million viewers.
The hour-long special followed the Good Morning Britain presenter, 53, and the couple’s two children, daughter Darcey, 15, and 11-year-old son Billy, throughout his ongoing illness.
Former political adviser Draper, also 53, remains in hospital after being admitted with coronavirus symptoms in March last year.
On Tuesday, Finding Derek averaged 4.5 million viewers, a peak of 4.7 million and a 24% share.
It was the most watched programme at 9pm and ITV’s biggest factual overnight audience in the Tuesday 9pm slot in more than a decade.
It was also the broadcaster’s biggest single documentary audience since The Queen’s Green Planet, featuring the Queen and Sir David Attenborough, in 2018.
Finding Derek detailed Garraway’s family’s experiences during Draper’s illness and featured her speaking to people suffering with long Covid, NHS staff and other experts.
One scene saw her recall being told by Draper’s doctors that he was the most seriously ill person they had seen who remained alive.
Garraway has been widely praised for her resilience in the wake of the show airing, with her Good Morning Britain co-star Ben Shephard, Piers Morgan, BBC Breakfast host Dan Walker and singer and TV presenter Myleene Klass all sharing public messages of support.