diff --git a/Code/Sandbox/Editor/CryEdit.cpp b/Code/Sandbox/Editor/CryEdit.cpp
index 815f986e1a..536821ca6c 100644
--- a/Code/Sandbox/Editor/CryEdit.cpp
+++ b/Code/Sandbox/Editor/CryEdit.cpp
@@ -53,6 +53,7 @@ AZ_POP_DISABLE_WARNING
 #include <AzCore/std/smart_ptr/make_shared.h>
 #include <AzCore/Settings/SettingsRegistryMergeUtils.h>
 #include <AzCore/Utils/Utils.h>
+#include <AzCore/Console/IConsole.h>
 
 // AzFramework
 #include <AzFramework/Components/CameraBus.h>
@@ -356,6 +357,8 @@ CCryEditDoc* CCryDocManager::OpenDocumentFile(LPCTSTR lpszFileName, BOOL bAddToM
     for (int i = idStart; i <= idEnd; ++i) \
         ON_COMMAND(i, method);
 
+AZ_CVAR_EXTERNED(bool, ed_previewGameInFullscreen_once);
+
 void CCryEditApp::RegisterActionHandlers()
 {
     ON_COMMAND(ID_APP_ABOUT, OnAppAbout)
@@ -377,8 +380,7 @@ void CCryEditApp::RegisterActionHandlers()
     ON_COMMAND(ID_FILE_EXPORTTOGAMENOSURFACETEXTURE, OnFileExportToGameNoSurfaceTexture)
     ON_COMMAND(ID_VIEW_SWITCHTOGAME, OnViewSwitchToGame)
     MainWindow::instance()->GetActionManager()->RegisterActionHandler(ID_VIEW_SWITCHTOGAME_FULLSCREEN, [this]() {
-        auto fs = gEnv->pConsole->GetCVar("ed_previewGameInFullscreen_once");
-        fs->Set(1);
+        ed_previewGameInFullscreen_once = true;
         OnViewSwitchToGame();
     });
     ON_COMMAND(ID_MOVE_OBJECT, OnMoveObject)
diff --git a/Code/Sandbox/Editor/EditorViewportWidget.cpp b/Code/Sandbox/Editor/EditorViewportWidget.cpp
index ba181aa99b..b02aafbe32 100644
--- a/Code/Sandbox/Editor/EditorViewportWidget.cpp
+++ b/Code/Sandbox/Editor/EditorViewportWidget.cpp
@@ -29,6 +29,7 @@
 #include <AzCore/Component/EntityId.h>
 #include <AzCore/Interface/Interface.h>
 #include <AzCore/Math/VectorConversions.h>
+#include <AzCore/Interface/Interface.h>
 #include <AzCore/Console/IConsole.h>
 
 // AzFramework
@@ -3059,6 +3060,8 @@ float EditorViewportSettings::AngleStep() const
     return SandboxEditor::AngleSnappingSize();
 }
 
+AZ_CVAR_EXTERNED(bool, ed_previewGameInFullscreen_once);
+
 bool EditorViewportWidget::ShouldPreviewFullscreen() const
 {
     CLayoutWnd* layout = GetIEditor()->GetViewManager()->GetLayout();
@@ -3089,23 +3092,10 @@ bool EditorViewportWidget::ShouldPreviewFullscreen() const
         }
     }
 
-    // Check 'ed_previewGameInFullscreen_once' and 'ed_previewGameInFullscreen' cvars
-    if (gEnv->pConsole)
+    // Check 'ed_previewGameInFullscreen_once'
+    if (ed_previewGameInFullscreen_once)
     {
-        if (auto v = gEnv->pConsole->GetCVar("ed_previewGameInFullscreen_once"))
-        {
-            if (v->GetIVal() != 0)
-            {
-                v->Set(0);
-                return true;
-            }
-        }
-
-        {
-            auto v = gEnv->pConsole->GetCVar("ed_previewGameInFullscreen");
-            return v && v->GetIVal() != 0; //  if it doesn't exist, assume its value is 0
-        }
-
+        ed_previewGameInFullscreen_once = true;
         return true;
     }
     else
@@ -3119,7 +3109,8 @@ void EditorViewportWidget::StartFullscreenPreview()
     AZ_Assert(!m_inFullscreenPreview, "EditorViewportWidget::StartFullscreenPreview called when already in full screen preview");
     m_inFullscreenPreview = true;
 
-    const QScreen* screen = QGuiApplication::primaryScreen();
+    // Pick the screen on which the main window lies to use as the screen for the full screen preview
+    const QScreen* screen = MainWindow::instance()->screen();
     const QRect screenGeometry = screen->geometry();
 
     // Unparent this and show it, which turns it into a free floating window
diff --git a/Code/Sandbox/Editor/Settings.cpp b/Code/Sandbox/Editor/Settings.cpp
index 66271a9967..f805e2e84b 100644
--- a/Code/Sandbox/Editor/Settings.cpp
+++ b/Code/Sandbox/Editor/Settings.cpp
@@ -26,6 +26,7 @@
 #include <AzCore/Settings/SettingsRegistryMergeUtils.h>
 #include <AzCore/StringFunc/StringFunc.h>
 #include <AzCore/Utils/Utils.h>
+#include <AzCore/Console/IConsole.h>
 
 // AzFramework
 #include <AzFramework/API/ApplicationAPI.h>
@@ -926,6 +927,8 @@ void SEditorSettings::Load()
 }
 
 //////////////////////////////////////////////////////////////////////////
+AZ_CVAR(bool, ed_previewGameInFullscreen_once, false, nullptr, AZ::ConsoleFunctorFlags::IsInvisible, "Preview the game (Ctrl+G, \"Play Game\", etc.) in fullscreen once");
+
 void SEditorSettings::PostInitApply()
 {
     if (!gEnv || !gEnv->pConsole)
@@ -947,12 +950,6 @@ void SEditorSettings::PostInitApply()
     REGISTER_CVAR2_CB("ed_keepEditorActive", &keepEditorActive, 0, VF_NULL, "Keep the editor active, even if no focus is set", KeepEditorActiveChanged);
     REGISTER_CVAR2("g_TemporaryLevelName", &g_TemporaryLevelName, "temp_level", VF_NULL, "Temporary level named used for experimental levels.");
 
-    REGISTER_INT("ed_previewGameInFullscreen", 0, VF_DEV_ONLY, "Preview the game (Ctrl+G, \"Play Game\", etc.) in fullscreen. 0 = no, 1 = yes");
-    gEnv->pConsole->GetCVar("ed_previewGameInFullscreen")->SetLimits(0, 1);
-
-    REGISTER_INT("ed_previewGameInFullscreen_once", 0, VF_DEV_ONLY | VF_INVISIBLE, "Preview the game (Ctrl+G, \"Play Game\", etc.) in fullscreen once. 0 = no, 1 = yes");
-    gEnv->pConsole->GetCVar("ed_previewGameInFullscreen_once")->SetLimits(0, 1);
-
     CCryEditApp::instance()->KeepEditorActive(keepEditorActive > 0);
 }