diff --git a/lnwallet/interface.go b/lnwallet/interface.go
index 88b261e05..c80d44797 100644
--- a/lnwallet/interface.go
+++ b/lnwallet/interface.go
@@ -278,13 +278,27 @@ type MessageSigner interface {
 	SignMessage(pubKey *btcec.PublicKey, msg []byte) (*btcec.Signature, error)
 }
 
+// PreimageCache is an interface that represents a global cache for preimages.
+// We'll utilize this cache to communicate the discovery of new preimages
+// across sub-systems.
+type PreimageCache interface {
+	// LookupPreimage attempts to look up a preimage according to its hash.
+	// If found, the preimage is returned along with true for the second
+	// argument. Otherwise, it'll return false.
+	LookupPreimage(hash []byte) ([]byte, bool)
+
+	// AddPreimage attempts to add a new preimage to the global cache. If
+	// successful a nil error will be returned.
+	AddPreimage(preimage []byte) error
+}
+
 // WalletDriver represents a "driver" for a particular concrete
 // WalletController implementation. A driver is identified by a globally unique
 // string identifier along with a 'New()' method which is responsible for
 // initializing a particular WalletController concrete implementation.
 type WalletDriver struct {
-	// WalletType is a string which uniquely identifies the WalletController
-	// that this driver, drives.
+	// WalletType is a string which uniquely identifies the
+	// WalletController that this driver, drives.
 	WalletType string
 
 	// New creates a new instance of a concrete WalletController