Cameron says the crisis session will be held Thursday, when Parliament would traditionally be on its summer recess.
He said Tuesday that there would be a clear government motion and vote on the British response to a chemical weapons attack in Syria.
Legislators had been urging Cameron to consult Parliament before any possible action against Syria.
THIS IS A BREAKING NEWS UPDATE.
AP's earlier story is below.
The British government said Tuesday its military is drawing up contingency plans for a possible military attack on Syria.
The possible military response would be in reaction to an alleged chemical attack on civilians in Syria.
Prime Minister David Cameron's office said that the UK is considering a "proportionate" response that would deter Syrian President Bashar Assad from using chemical weapons in the future.
Cameron is facing pressure to recall Parliament later this week to discuss the crisis in Syria. Officials said a decision on whether to bring Parliament back from its summer recess early would be made later Tuesday.
Britain's Ministry of Defense also said that a planned Royal Air Force training mission involving British Typhoon fighter jets has been postponed. The jets were to have been deployed on the Mediterranean island of Cyprus.