diff --git a/demos/cast/build.gradle b/demos/cast/build.gradle
index c928d0e46e..ae6bdd1d94 100644
--- a/demos/cast/build.gradle
+++ b/demos/cast/build.gradle
@@ -29,7 +29,10 @@ android {
         release {
             shrinkResources true
             minifyEnabled true
-            proguardFiles getDefaultProguardFile('proguard-android.txt')
+            proguardFiles = [
+                "proguard-rules.txt",
+                getDefaultProguardFile('proguard-android.txt')
+            ]
         }
         debug {
             jniDebuggable = true
diff --git a/demos/cast/proguard-rules.txt b/demos/cast/proguard-rules.txt
new file mode 100644
index 0000000000..3221818080
--- /dev/null
+++ b/demos/cast/proguard-rules.txt
@@ -0,0 +1,6 @@
+# Proguard rules specific to the Cast demo app.
+
+# Accessed via menu.xml
+-keep class android.support.v7.app.MediaRouteActionProvider {
+  *;
+}