diff --git a/htlcswitch/mock.go b/htlcswitch/mock.go
index c56b47548..fe4bbacde 100644
--- a/htlcswitch/mock.go
+++ b/htlcswitch/mock.go
@@ -1011,6 +1011,7 @@ func newMockRegistry(minDelta uint32) *mockInvoiceRegistry {
 		panic(err)
 	}
 
+	modifierMock := &invoices.MockHtlcModifier{}
 	registry := invoices.NewRegistry(
 		cdb,
 		invoices.NewInvoiceExpiryWatcher(
@@ -1019,6 +1020,7 @@ func newMockRegistry(minDelta uint32) *mockInvoiceRegistry {
 		),
 		&invoices.RegistryConfig{
 			FinalCltvRejectDelta: 5,
+			HtlcModifier:         modifierMock,
 		},
 	)
 	registry.Start()
diff --git a/invoices/invoiceregistry.go b/invoices/invoiceregistry.go
index de731b474..2e28be366 100644
--- a/invoices/invoiceregistry.go
+++ b/invoices/invoiceregistry.go
@@ -74,6 +74,11 @@ type RegistryConfig struct {
 	// KeysendHoldTime indicates for how long we want to accept and hold
 	// spontaneous keysend payments.
 	KeysendHoldTime time.Duration
+
+	// HtlcModifier is a service that intercepts invoice HTLCs during the
+	// settlement phase, enabling a subscribed client to modify certain
+	// aspects of those HTLCs.
+	HtlcModifier HtlcModifier
 }
 
 // htlcReleaseEvent describes an htlc auto-release event. It is used to release
@@ -998,6 +1003,53 @@ func (i *InvoiceRegistry) notifyExitHopHtlcLocked(
 	)
 
 	callback := func(inv *Invoice) (*InvoiceUpdateDesc, error) {
+		// Provide the invoice to the settlement interceptor to allow
+		// the interceptor's client an opportunity to manipulate the
+		// settlement process.
+		clientReq := HtlcModifyRequest{
+			ExitHtlcCircuitKey: ctx.circuitKey,
+			ExitHtlcAmt:        ctx.amtPaid,
+			ExitHtlcExpiry:     ctx.expiry,
+			CurrentHeight:      uint32(ctx.currentHeight),
+			Invoice:            *inv,
+		}
+		interceptSession := i.cfg.HtlcModifier.Intercept(
+			clientReq,
+		)
+
+		// If the interceptor service has provided a response, we'll
+		// use the interceptor session to wait for the client to respond
+		// with a settlement resolution.
+		var interceptErr error
+		interceptSession.WhenSome(func(session InterceptSession) {
+			log.Debug("Waiting for client response from invoice " +
+				"HTLC interceptor session")
+
+			select {
+			case resp := <-session.ClientResponseChannel:
+				log.Debugf("Received invoice HTLC interceptor "+
+					"response: %v", resp)
+
+				if resp.AmountPaid != 0 {
+					ctx.amtPaid = resp.AmountPaid
+				}
+
+			case err := <-session.ClientErrChannel:
+				log.Errorf("Error from invoice HTLC "+
+					"interceptor session: %v", err)
+
+				interceptErr = err
+
+			case <-session.Quit:
+				// At this point, the interceptor session has
+				// quit.
+			}
+		})
+		if interceptErr != nil {
+			return nil, fmt.Errorf("error during invoice HTLC "+
+				"interception: %w", interceptErr)
+		}
+
 		updateDesc, res, err := updateInvoice(ctx, inv)
 		if err != nil {
 			return nil, err
@@ -1051,6 +1103,8 @@ func (i *InvoiceRegistry) notifyExitHopHtlcLocked(
 
 	var invoiceToExpire invoiceExpiry
 
+	log.Tracef("Settlement resolution: %T %v", resolution, resolution)
+
 	switch res := resolution.(type) {
 	case *HtlcFailResolution:
 		// Inspect latest htlc state on the invoice. If it is found,
@@ -1183,7 +1237,7 @@ func (i *InvoiceRegistry) notifyExitHopHtlcLocked(
 	}
 
 	// Now that the links have been notified of any state changes to their
-	// HTLCs, we'll go ahead and notify any clients wiaiting on the invoice
+	// HTLCs, we'll go ahead and notify any clients waiting on the invoice
 	// state changes.
 	if updateSubscribers {
 		// We'll add a setID onto the notification, but only if this is
diff --git a/invoices/invoiceregistry_test.go b/invoices/invoiceregistry_test.go
index b0c019522..78de71883 100644
--- a/invoices/invoiceregistry_test.go
+++ b/invoices/invoiceregistry_test.go
@@ -23,6 +23,12 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+var (
+	// htlcModifierMock is a mock implementation of the invoice HtlcModifier
+	// interface.
+	htlcModifierMock = &invpkg.MockHtlcModifier{}
+)
+
 // TestInvoiceRegistry is a master test which encompasses all tests using an
 // InvoiceDB instance. The purpose of this test is to be able to run all tests
 // with a custom DB instance, so that we can test the same logic with different
@@ -517,6 +523,7 @@ func testSettleHoldInvoice(t *testing.T,
 	cfg := invpkg.RegistryConfig{
 		FinalCltvRejectDelta: testFinalCltvRejectDelta,
 		Clock:                clock,
+		HtlcModifier:         htlcModifierMock,
 	}
 
 	expiryWatcher := invpkg.NewInvoiceExpiryWatcher(
@@ -683,6 +690,7 @@ func testCancelHoldInvoice(t *testing.T,
 	cfg := invpkg.RegistryConfig{
 		FinalCltvRejectDelta: testFinalCltvRejectDelta,
 		Clock:                testClock,
+		HtlcModifier:         htlcModifierMock,
 	}
 	expiryWatcher := invpkg.NewInvoiceExpiryWatcher(
 		cfg.Clock, 0, uint32(testCurrentHeight), nil, newMockNotifier(),
@@ -1200,6 +1208,7 @@ func testInvoiceExpiryWithRegistry(t *testing.T,
 	cfg := invpkg.RegistryConfig{
 		FinalCltvRejectDelta: testFinalCltvRejectDelta,
 		Clock:                testClock,
+		HtlcModifier:         htlcModifierMock,
 	}
 
 	expiryWatcher := invpkg.NewInvoiceExpiryWatcher(
@@ -1310,6 +1319,7 @@ func testOldInvoiceRemovalOnStart(t *testing.T,
 		FinalCltvRejectDelta:        testFinalCltvRejectDelta,
 		Clock:                       testClock,
 		GcCanceledInvoicesOnStartup: true,
+		HtlcModifier:                htlcModifierMock,
 	}
 
 	expiryWatcher := invpkg.NewInvoiceExpiryWatcher(
diff --git a/invoices/test_utils_test.go b/invoices/test_utils_test.go
index a0adf7dc8..aca5f3eac 100644
--- a/invoices/test_utils_test.go
+++ b/invoices/test_utils_test.go
@@ -143,6 +143,7 @@ func defaultRegistryConfig() invpkg.RegistryConfig {
 	return invpkg.RegistryConfig{
 		FinalCltvRejectDelta: testFinalCltvRejectDelta,
 		HtlcHoldDuration:     30 * time.Second,
+		HtlcModifier:         &invpkg.MockHtlcModifier{},
 	}
 }