diff --git a/graphics/include/ignition/common/Animation.hh b/graphics/include/ignition/common/Animation.hh
index 65209519d..c0843519f 100644
--- a/graphics/include/ignition/common/Animation.hh
+++ b/graphics/include/ignition/common/Animation.hh
@@ -34,7 +34,6 @@ namespace ignition
     class KeyFrame;
     class PoseKeyFrame;
     class NumericKeyFrame;
-    class AnimationPrivate;
     class TrajectoryInfoPrivate;
 
     /// \class Animation Animation.hh ignition/common/Animation.hh
diff --git a/graphics/src/Animation.cc b/graphics/src/Animation.cc
index 272ccb5eb..a8d7d76b0 100644
--- a/graphics/src/Animation.cc
+++ b/graphics/src/Animation.cc
@@ -40,11 +40,15 @@ namespace
 }
 
 /////////////////////////////////////////////////
-class ignition::common::AnimationPrivate
+namespace ignition {
+namespace common {
+class AnimationPrivate
 {
   /// \brief true if the animation is interpolated in x
   public: bool interpolateX = false;
 };
+}  // namespace ignition
+}  // namespace common
 
 // TODO(luca) Make Animation class follow PIMPL and remove global static map
 /////////////////////////////////////////////////