diff --git a/Modules/CMakeAddFortranSubdirectory.cmake b/Modules/CMakeAddFortranSubdirectory.cmake
index 534f99eeaf..b87d0ad4ec 100644
--- a/Modules/CMakeAddFortranSubdirectory.cmake
+++ b/Modules/CMakeAddFortranSubdirectory.cmake
@@ -233,7 +233,7 @@ function(cmake_add_fortran_subdirectory subdir)
   # create build and configure wrapper scripts
   _setup_mingw_config_and_build("${source_dir}" "${build_dir}")
   # create the external project
-  externalproject_add(${project_name}_build
+  ExternalProject_Add(${project_name}_build
     SOURCE_DIR ${source_dir}
     BINARY_DIR ${build_dir}
     CONFIGURE_COMMAND ${CMAKE_COMMAND}