I'm a Celebrity attracts 11.5m viewers
I'm a Celebrity... Get Me Out of Here! was watched by an average audience of 11.5 million, according to overnight data - a record opening for the show.
The ITV1 programme, featuring comic Freddie Starr and The Only Way is Essex's Mark Wright, was watched by a peak audience of 12.5 million.
Garrow's Law, in the same 21:00 slot on BBC One, attracted 4.9 million viewers.
Sunday's figures built on last year's opening episode ratings of 11.2 million.
The overnight average figure of 11.5 million includes viewers on ITV1 HD, while ITV said a further 300,000 viewers watched Sunday night's programme on catch-up service ITV1+1.
Opening night average audience figures for other big entertainment shows include the 10.5 million who watched ITV's X Factor on 20 August and 9.1 million people who watched BBC's Strictly Come Dancing on 30 September.
Actors Lorraine Chase, Stefanie Powers and Coronation Street's Antony Cotton were among the hopefuls shown entering the jungle on Sunday night's programme.
Viewers watched as McFly bassist Dougie Poynter asked comic Freddie Starr about the infamous headline claiming he once ate a hamster.
"No, I couldn't crack its skull," Starr replied.
"You couldn't eat a hamster.
"If you were to eat a hamster you'd choke - you couldn't actually eat a hamster," the funnyman replied.
Starr was later taken to hospital after he became ill following a bushtucker trial called "greasy spoon" in which he had to eat a selection of insects.
A spokesman for the show said the comedian was undergoing tests and would stay in hospital overnight "as a precaution".