diff --git a/src/net/smtp/smtp.go b/src/net/smtp/smtp.go
index ab457d3f957..bf574aece1c 100644
--- a/src/net/smtp/smtp.go
+++ b/src/net/smtp/smtp.go
@@ -67,6 +67,7 @@ func NewClient(conn net.Conn, host string) (*Client, error) {
 		return nil, err
 	}
 	c := &Client{Text: text, conn: conn, serverName: host, localName: "localhost"}
+	_, c.tls = conn.(*tls.Conn)
 	return c, nil
 }
 
diff --git a/src/net/smtp/smtp_test.go b/src/net/smtp/smtp_test.go
index e4549d251e9..9e7ed78f365 100644
--- a/src/net/smtp/smtp_test.go
+++ b/src/net/smtp/smtp_test.go
@@ -373,6 +373,53 @@ HELO localhost
 QUIT
 `
 
+func TestNewClientWithTLS(t *testing.T) {
+	cert, err := tls.X509KeyPair(localhostCert, localhostKey)
+	if err != nil {
+		t.Fatalf("loadcert: %v", err)
+	}
+
+	config := tls.Config{Certificates: []tls.Certificate{cert}}
+
+	ln, err := tls.Listen("tcp", "127.0.0.1:0", &config)
+	if err != nil {
+		ln, err = tls.Listen("tcp", "[::1]:0", &config)
+		if err != nil {
+			t.Fatalf("server: listen: %s", err)
+		}
+	}
+
+	go func() {
+		conn, err := ln.Accept()
+		if err != nil {
+			t.Fatalf("server: accept: %s", err)
+			return
+		}
+		defer conn.Close()
+
+		_, err = conn.Write([]byte("220 SIGNS\r\n"))
+		if err != nil {
+			t.Fatalf("server: write: %s", err)
+			return
+		}
+	}()
+
+	config.InsecureSkipVerify = true
+	conn, err := tls.Dial("tcp", ln.Addr().String(), &config)
+	if err != nil {
+		t.Fatalf("client: dial: %s", err)
+	}
+	defer conn.Close()
+
+	client, err := NewClient(conn, ln.Addr().String())
+	if err != nil {
+		t.Fatalf("smtp: newclient: %s", err)
+	}
+	if !client.tls {
+		t.Errorf("client.tls Got: %t Expected: %t", client.tls, true)
+	}
+}
+
 func TestHello(t *testing.T) {
 
 	if len(helloServer) != len(helloClient) {