Philip Hammond will call for a "radical shift" in the role of reservists, who he will say have for too long been "the forgotten part of our Armed Forces".
We're looking for people who are going to turn out when they're required to turn out, who are going to do the training they need to do and who are available for deployment.
So the message to future reservists is clear: promise us you will make the commitment; turn up regularly to train and be prepared to deploy. And in return, we promise to equip you, train you, fund you and use you as an integral part of the British Army.
Mr Hammond will also pledge a "fresh start" in the Government's relationship with reservists, who will in future be required to routinely share responsibility for "activities once the exclusive domain of regular forces".