diff --git a/gst-libs/gst/gl/gstglutils_private.h b/gst-libs/gst/gl/gstglutils_private.h
index 008fcc6dcb..64194a6efc 100644
--- a/gst-libs/gst/gl/gstglutils_private.h
+++ b/gst-libs/gst/gl/gstglutils_private.h
@@ -25,8 +25,8 @@
 
 G_BEGIN_DECLS
 
-gboolean gst_gl_run_query (GstElement * element, GstQuery * query, GstPadDirection direction);
-void gst_gl_get_affine_transformation_meta_as_ndc (GstVideoAffineTransformationMeta * meta, gfloat * matrix);
+G_GNUC_INTERNAL gboolean gst_gl_run_query (GstElement * element, GstQuery * query, GstPadDirection direction);
+G_GNUC_INTERNAL void gst_gl_get_affine_transformation_meta_as_ndc (GstVideoAffineTransformationMeta * meta, gfloat * matrix);
 
 G_END_DECLS