The United States and the European Union are to hold negotiations on what could be the world's largest trade deal.
The talks were announced before the G8 summit began in Northern Ireland on Monday.
President Barack Obama said the first round of negotiations would take place in Washington in July. They aim to conclude by the end of 2014.
British Prime Minister David Cameron said the deal could be worth £100 billion to the EU economy, £80 billion to the United States and £85 billion to the rest of the world.
He said the pact could create two million jobs and lead to more choice and lower prices in shops.
"This is a once-in-a-generation prize and we are determined to seize it," Mr Cameron said.
The BBC reports free trade between the United States and the EU has been under discussion for several years and a working group was established in 2011 to discuss the prospect of a free trade agreement.
The EU has said the deal will focus on bringing down remaining tariffs and other barriers to trade, and standardise technical regulations and certifications.
However, EU ministers agreed on Friday to demands by France for the film and television industry to be excluded from the talks.
Agriculture is also expected to be a significant bone of contention.