diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index bbeeeed43..4ba8537e0 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -1160,7 +1160,7 @@ function(_ep_command_line_to_initial_cache var args force)
       endif()
     else()
       # Assume this is a list to append to the last var
-      list(APPEND accumulator "${line}")
+      string(APPEND accumulator ";${line}")
     endif()
   endforeach()
   # Catch the final line of the args
diff --git a/Tests/RunCMake/ExternalProject/CMAKE_CACHE_ARGS-check.cmake b/Tests/RunCMake/ExternalProject/CMAKE_CACHE_ARGS-check.cmake
index c350a63fc..cb48be7e0 100644
--- a/Tests/RunCMake/ExternalProject/CMAKE_CACHE_ARGS-check.cmake
+++ b/Tests/RunCMake/ExternalProject/CMAKE_CACHE_ARGS-check.cmake
@@ -15,3 +15,12 @@ if(NOT "${CMAKE_MATCH_0}" MATCHES FORCE)
   set(RunCMake_TEST_FAILED "Expected forced FOO argument")
   return()
 endif()
+
+if(NOT "${_cache}" MATCHES "set\\(TEST_LIST \"A;B;C\".+\\)")
+  set(RunCMake_TEST_FAILED "Cannot find TEST_LIST argument in cache")
+  return()
+endif()
+if(NOT "${CMAKE_MATCH_0}" MATCHES FORCE)
+  set(RunCMake_TEST_FAILED "Expected forced TEST_LIST argument")
+  return()
+endif()
diff --git a/Tests/RunCMake/ExternalProject/CMAKE_CACHE_ARGS.cmake b/Tests/RunCMake/ExternalProject/CMAKE_CACHE_ARGS.cmake
index 62b164040..1f76fd03e 100644
--- a/Tests/RunCMake/ExternalProject/CMAKE_CACHE_ARGS.cmake
+++ b/Tests/RunCMake/ExternalProject/CMAKE_CACHE_ARGS.cmake
@@ -5,4 +5,6 @@ include(ExternalProject)
 
 ExternalProject_Add(FOO TMP_DIR "${CMAKE_CURRENT_BINARY_DIR}/tmp"
                         DOWNLOAD_COMMAND ""
-                        CMAKE_CACHE_ARGS "-DFOO:STRING=$<1:BAR>$<0:BAD>")
+                        CMAKE_CACHE_ARGS
+                            "-DFOO:STRING=$<1:BAR>$<0:BAD>"
+                            "-DTEST_LIST:STRING=A;B;C")
diff --git a/Tests/RunCMake/ExternalProject/CMAKE_CACHE_DEFAULT_ARGS-check.cmake b/Tests/RunCMake/ExternalProject/CMAKE_CACHE_DEFAULT_ARGS-check.cmake
index aeee11fa0..c84932d60 100644
--- a/Tests/RunCMake/ExternalProject/CMAKE_CACHE_DEFAULT_ARGS-check.cmake
+++ b/Tests/RunCMake/ExternalProject/CMAKE_CACHE_DEFAULT_ARGS-check.cmake
@@ -15,3 +15,12 @@ if("${CMAKE_MATCH_0}" MATCHES FORCE)
   set(RunCMake_TEST_FAILED "Expected not forced FOO argument")
   return()
 endif()
+
+if(NOT "${_cache}" MATCHES "set\\(TEST_LIST \"A;B;C\".+\\)")
+  set(RunCMake_TEST_FAILED "Cannot find TEST_LIST argument in cache")
+  return()
+endif()
+if("${CMAKE_MATCH_0}" MATCHES FORCE)
+  set(RunCMake_TEST_FAILED "Expected not forced TEST_LIST argument")
+  return()
+endif()
diff --git a/Tests/RunCMake/ExternalProject/CMAKE_CACHE_DEFAULT_ARGS.cmake b/Tests/RunCMake/ExternalProject/CMAKE_CACHE_DEFAULT_ARGS.cmake
index 3a83dbe38..1b619c8c0 100644
--- a/Tests/RunCMake/ExternalProject/CMAKE_CACHE_DEFAULT_ARGS.cmake
+++ b/Tests/RunCMake/ExternalProject/CMAKE_CACHE_DEFAULT_ARGS.cmake
@@ -5,4 +5,6 @@ include(ExternalProject)
 
 ExternalProject_Add(FOO TMP_DIR "${CMAKE_CURRENT_BINARY_DIR}/tmp"
                         DOWNLOAD_COMMAND ""
-                        CMAKE_CACHE_DEFAULT_ARGS "-DFOO:STRING=$<1:BAR>$<0:BAD>")
+                        CMAKE_CACHE_DEFAULT_ARGS
+                            "-DFOO:STRING=$<1:BAR>$<0:BAD>"
+                            "-DTEST_LIST:STRING=A;B;C")