diff --git a/Kconfig b/Kconfig
index 745bc773f567..57a142d8d8b4 100644
--- a/Kconfig
+++ b/Kconfig
@@ -30,3 +30,6 @@ source "lib/Kconfig"
 source "lib/Kconfig.debug"
 
 source "Documentation/Kconfig"
+
+# ANDROID: Set KCONFIG_EXT_PREFIX to decend into an external project.
+source "$(KCONFIG_EXT_PREFIX)Kconfig.ext"
diff --git a/Kconfig.ext b/Kconfig.ext
new file mode 100644
index 000000000000..48d805f0bfc0
--- /dev/null
+++ b/Kconfig.ext
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+# This file is intentionally empty. It's used as a placeholder for when
+# KCONFIG_EXT_PREFIX isn't defined.