diff --git a/extensions/cast/build.gradle b/extensions/cast/build.gradle
index 8780b961d6..d7e99573cb 100644
--- a/extensions/cast/build.gradle
+++ b/extensions/cast/build.gradle
@@ -21,6 +21,7 @@ android {
     defaultConfig {
         minSdkVersion 14
         targetSdkVersion project.ext.targetSdkVersion
+        consumerProguardFiles 'proguard-rules.txt'
     }
 }
 
diff --git a/extensions/cast/proguard-rules.txt b/extensions/cast/proguard-rules.txt
new file mode 100644
index 0000000000..bc94b33c1c
--- /dev/null
+++ b/extensions/cast/proguard-rules.txt
@@ -0,0 +1,4 @@
+# Proguard rules specific to the Cast extension.
+
+# DefaultCastOptionsProvider is commonly referred to only by the app's manifest.
+-keep class com.google.android.exoplayer2.ext.cast.DefaultCastOptionsProvider