A ban on product placement has been lifted, allowing advertisers to pay for their goods to be seen on British TV.
Paid-for references to products and services are now permitted for the first time in shows produced in the UK, including soaps and one-off dramas.
The first product, a Nescafe coffee machine, has appeared on This Morning.
The Church of England and doctors' leaders have opposed the move, saying it could damage trust in broadcasters and promote unhealthy lifestyles.
Under Ofcom regulations, broadcasters must inform viewers by displaying the letter 'P' for three seconds at the start and end of a programme that contains product placement.
The telecoms regulator has said any placement must be editorially justified and not unduly prominent.
It will not be allowed in news, current affairs or children's programmes - or for alcoholic drinks and foods high in salt, sugar and fat.
And it will continue to be banned for BBC shows.
In the United States, advertisers such as Coca-Cola and Apple pay millions of dollars to place their products in films and TV programmes.
When the European Union lifted its ban on such payments, there was heated debate over whether it should be allowed in productions made in the UK.
Commercial broadcasters and independent producers argued it would help pay for programmes.
But Church leaders were among those who said it could damage trust and promote unhealthy lifestyles.
The last Labour government eventually gave the go-ahead, but only after setting out strict limitations.