diff --git a/core/object.cpp b/core/object.cpp
index ea77090a455..3a14c7c0b55 100644
--- a/core/object.cpp
+++ b/core/object.cpp
@@ -1443,8 +1443,20 @@ Error Object::connect(const StringName &p_signal, Object *p_to_object, const Str
 	if (!s) {
 		bool signal_is_valid = ClassDB::has_signal(get_class_name(), p_signal);
 		//check in script
-		if (!signal_is_valid && !script.is_null() && Ref<Script>(script)->has_script_signal(p_signal))
-			signal_is_valid = true;
+		if (!signal_is_valid && !script.is_null()) {
+
+			if (Ref<Script>(script)->has_script_signal(p_signal)) {
+				signal_is_valid = true;
+			}
+#ifdef TOOLS_ENABLED
+			else {
+				//allow connecting signals anyway if script is invalid, see issue #17070
+				if (!Ref<Script>(script)->is_valid()) {
+					signal_is_valid = true;
+				}
+			}
+#endif
+		}
 
 		if (!signal_is_valid) {
 			ERR_EXPLAIN("In Object of type '" + String(get_class()) + "': Attempt to connect nonexistent signal '" + p_signal + "' to method '" + p_to_object->get_class() + "." + p_to_method + "'");
diff --git a/core/script_language.h b/core/script_language.h
index bcd9c2c5eab..654d1d42653 100644
--- a/core/script_language.h
+++ b/core/script_language.h
@@ -128,6 +128,7 @@ public:
 	virtual MethodInfo get_method_info(const StringName &p_method) const = 0;
 
 	virtual bool is_tool() const = 0;
+	virtual bool is_valid() const = 0;
 
 	virtual ScriptLanguage *get_language() const = 0;
 
diff --git a/modules/gdnative/nativescript/nativescript.cpp b/modules/gdnative/nativescript/nativescript.cpp
index eb133502c4d..bcaf3f346ef 100644
--- a/modules/gdnative/nativescript/nativescript.cpp
+++ b/modules/gdnative/nativescript/nativescript.cpp
@@ -294,6 +294,10 @@ MethodInfo NativeScript::get_method_info(const StringName &p_method) const {
 	return MethodInfo();
 }
 
+bool NativeScript::is_valid() const {
+	return true;
+}
+
 bool NativeScript::is_tool() const {
 	NativeScriptDesc *script_data = get_script_desc();
 
diff --git a/modules/gdnative/nativescript/nativescript.h b/modules/gdnative/nativescript/nativescript.h
index 51370f5fbf5..e6f3c06ee56 100644
--- a/modules/gdnative/nativescript/nativescript.h
+++ b/modules/gdnative/nativescript/nativescript.h
@@ -160,6 +160,7 @@ public:
 	virtual MethodInfo get_method_info(const StringName &p_method) const;
 
 	virtual bool is_tool() const;
+	virtual bool is_valid() const;
 
 	virtual ScriptLanguage *get_language() const;
 
diff --git a/modules/gdnative/pluginscript/pluginscript_script.h b/modules/gdnative/pluginscript/pluginscript_script.h
index 31c6c4d67ff..3ade8ac0048 100644
--- a/modules/gdnative/pluginscript/pluginscript_script.h
+++ b/modules/gdnative/pluginscript/pluginscript_script.h
@@ -102,6 +102,7 @@ public:
 	PropertyInfo get_property_info(const StringName &p_property) const;
 
 	bool is_tool() const { return _tool; }
+	bool is_valid() const { return true; }
 
 	virtual ScriptLanguage *get_language() const;
 
diff --git a/modules/gdscript/gdscript.cpp b/modules/gdscript/gdscript.cpp
index 1f5f5035f99..538249c8e23 100644
--- a/modules/gdscript/gdscript.cpp
+++ b/modules/gdscript/gdscript.cpp
@@ -867,7 +867,6 @@ bool GDScript::has_script_signal(const StringName &p_signal) const {
 	else if (base_cache.is_valid()) {
 		return base_cache->has_script_signal(p_signal);
 	}
-
 #endif
 	return false;
 }
diff --git a/modules/gdscript/gdscript.h b/modules/gdscript/gdscript.h
index f344beba9fd..752d660ffb8 100644
--- a/modules/gdscript/gdscript.h
+++ b/modules/gdscript/gdscript.h
@@ -141,7 +141,7 @@ protected:
 	static void _bind_methods();
 
 public:
-	bool is_valid() const { return valid; }
+	virtual bool is_valid() const { return valid; }
 
 	const Map<StringName, Ref<GDScript> > &get_subclasses() const { return subclasses; }
 	const Map<StringName, Variant> &get_constants() const { return constants; }
diff --git a/modules/mono/csharp_script.cpp b/modules/mono/csharp_script.cpp
index 700e518cfcf..0a54ed5fbd5 100644
--- a/modules/mono/csharp_script.cpp
+++ b/modules/mono/csharp_script.cpp
@@ -2571,6 +2571,10 @@ void CSharpScript::update_exports() {
 #endif
 }
 
+bool CSharpScript::is_valid() const {
+	return true; //TODO return false if invalid
+}
+
 bool CSharpScript::has_script_signal(const StringName &p_signal) const {
 	if (_signals.has(p_signal))
 		return true;
diff --git a/modules/mono/csharp_script.h b/modules/mono/csharp_script.h
index fc604df2a07..871d4d7e4c6 100644
--- a/modules/mono/csharp_script.h
+++ b/modules/mono/csharp_script.h
@@ -158,6 +158,8 @@ public:
 	virtual void update_exports();
 
 	virtual bool is_tool() const { return tool; }
+	virtual bool is_valid() const;
+
 	virtual Ref<Script> get_base_script() const;
 	virtual ScriptLanguage *get_language() const;
 
diff --git a/modules/visual_script/visual_script.cpp b/modules/visual_script/visual_script.cpp
index 186e9e63b1d..5b3b3a67692 100644
--- a/modules/visual_script/visual_script.cpp
+++ b/modules/visual_script/visual_script.cpp
@@ -981,6 +981,10 @@ bool VisualScript::is_tool() const {
 	return false;
 }
 
+bool VisualScript::is_valid() const {
+	return true; //always valid
+}
+
 ScriptLanguage *VisualScript::get_language() const {
 
 	return VisualScriptLanguage::singleton;
diff --git a/modules/visual_script/visual_script.h b/modules/visual_script/visual_script.h
index bd666447a36..cdc9159a73b 100644
--- a/modules/visual_script/visual_script.h
+++ b/modules/visual_script/visual_script.h
@@ -341,6 +341,7 @@ public:
 	virtual Error reload(bool p_keep_state = false);
 
 	virtual bool is_tool() const;
+	virtual bool is_valid() const;
 
 	virtual ScriptLanguage *get_language() const;