The ad, created by Mother, features presenters spoofing a TV shopping channel to highlight the ease with which weapons can be bought and sold.
The cinema ad, which was shot by Dougal Wilson at Blink Productions, is part of a multimedia campaign to get 1m people to sign Amnesty's petition.
The campaign is calling on the United Nations to introduce an international arms trade treaty that would create legally binding arms controls and ensure that all governments regulate arms sales to the same basic international standards.
The ad will run in cinemas nationwide for four weeks and will be seen by an estimated 2m people. Media space has been provided free by cinema advertising group Pearl & Dean.
The campaign includes a direct mail element created by A Different Kettle. It takes the form of a glossy mail order "small arms catalogue" from the fictitious Teleshop company, shot by photographer Sean Gleason.
The mailing shows models posing with machine guns and automatic pistols and will be sent to all Amnesty supporters and will then roll out on a wider basis.
A viral email campaign will surprise online users with fake special offers for weapons and a "roadshow" will tour shopping centres across the country with fake salespeople demonstrating the ease with which an AK-47 can be assembled and fired.
Kate Allen, director of Amnesty International in the UK, said: "Some people might find our Teleshop ad disturbing. But what's truly shocking is that one person dies every minute from armed violence. And there is a scandalous lack of controls to stop weapons getting into the wrong hands. In some countries, people tell us that guns are as easy to come by as a pack of cigarettes."
The UK is one of more than 40 countries that have stated their support for such a treaty. The global arms trade is worth $21bn (£11.7bn) a year.
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