diff --git a/runtimes/google/rt/rt.go b/runtimes/google/rt/rt.go
index f3f9822..d33e95e 100644
--- a/runtimes/google/rt/rt.go
+++ b/runtimes/google/rt/rt.go
@@ -61,6 +61,8 @@
 	nsRoots := []string{}
 	for _, o := range opts {
 		switch v := o.(type) {
+		case veyron2.RuntimePrincipal:
+			rt.principal = v.Principal
 		case veyron2.RuntimeIDOpt:
 			rt.id = v.PrivateID
 		case veyron2.RuntimePublicIDStoreOpt:
diff --git a/runtimes/google/rt/rt_test.go b/runtimes/google/rt/rt_test.go
index 51f2031..05164f0 100644
--- a/runtimes/google/rt/rt_test.go
+++ b/runtimes/google/rt/rt_test.go
@@ -20,6 +20,7 @@
 	"veyron.io/veyron/veyron/lib/modules"
 	_ "veyron.io/veyron/veyron/lib/testutil"
 	irt "veyron.io/veyron/veyron/runtimes/google/rt"
+	vsecurity "veyron.io/veyron/veyron/security"
 )
 
 type context struct {
@@ -159,3 +160,19 @@
 		t.Fatalf("Initialized Principal: %v, expected: %v", got.PublicKey(), p.PublicKey())
 	}
 }
+
+func TestInitPrincipalFromOption(t *testing.T) {
+	p, err := vsecurity.NewPrincipal()
+	if err != nil {
+		t.Fatalf("NewPrincipal() failed: %v", err)
+	}
+
+	r, err := rt.New(veyron2.RuntimePrincipal{p})
+	if err != nil {
+		t.Fatalf("rt.New failed: %v", err)
+	}
+
+	if got := r.Principal(); !reflect.DeepEqual(got, p) {
+		t.Fatalf("r.Principal(): got %v, want %v", got, p)
+	}
+}
diff --git a/runtimes/google/rt/security.go b/runtimes/google/rt/security.go
index f034ce7..d141d3e 100644
--- a/runtimes/google/rt/security.go
+++ b/runtimes/google/rt/security.go
@@ -49,6 +49,9 @@
 }
 
 func (rt *vrt) initPrincipal() error {
+	if rt.principal != nil {
+		return nil
+	}
 	// TODO(ataly, ashankar): Check if agent environment variables are
 	// specified and if so initialize principal from agent.
 	var err error