diff --git a/pkg/build/types/types.go b/pkg/build/types/types.go
index f2bd9286e..c4869abed 100644
--- a/pkg/build/types/types.go
+++ b/pkg/build/types/types.go
@@ -88,7 +88,7 @@ type ImageContents struct {
 	// A list of packages to include in the image
 	Packages []string `json:"packages,omitempty" yaml:"packages,omitempty"`
 	// Optional: Base image to build on top of. Warning: Experimental.
-	BaseImage *BaseImageDescriptor `json:"baseimage,omitempty" yaml:"baseimage,omitempty"`
+	BaseImage *BaseImageDescriptor `json:"baseimage,omitempty" yaml:"baseimage,omitempty" apko:"experimental"`
 }
 
 // MarshalYAML implements yaml.Marshaler for ImageContents, redacting URLs in