diff --git a/Marlin/src/module/stepper.h b/Marlin/src/module/stepper.h
index 787599ce31..d8fb5af229 100644
--- a/Marlin/src/module/stepper.h
+++ b/Marlin/src/module/stepper.h
@@ -316,6 +316,8 @@ constexpr ena_mask_t enable_overlap[] = {
 // Stepper class definition
 //
 class Stepper {
+  friend class KinematicSystem;
+  friend class DeltaKinematicSystem;
 
   public: