diff --git a/core/string/ustring.cpp b/core/string/ustring.cpp
index 5a42a3af127..9be7c041583 100644
--- a/core/string/ustring.cpp
+++ b/core/string/ustring.cpp
@@ -3974,24 +3974,22 @@ bool String::is_absolute_path() const {
 	}
 }
 
-static _FORCE_INLINE_ bool _is_valid_identifier_bit(int p_index, char32_t p_char) {
-	if (p_index == 0 && is_digit(p_char)) {
-		return false; // No start with number plz.
-	}
-	return is_ascii_identifier_char(p_char);
-}
-
 String String::validate_identifier() const {
 	if (is_empty()) {
 		return "_"; // Empty string is not a valid identifier;
 	}
 
-	String result = *this;
+	String result;
+	if (is_digit(operator[](0))) {
+		result = "_" + *this;
+	} else {
+		result = *this;
+	}
+
 	int len = result.length();
 	char32_t *buffer = result.ptrw();
-
 	for (int i = 0; i < len; i++) {
-		if (!_is_valid_identifier_bit(i, buffer[i])) {
+		if (!is_ascii_identifier_char(buffer[i])) {
 			buffer[i] = '_';
 		}
 	}
@@ -4006,10 +4004,14 @@ bool String::is_valid_identifier() const {
 		return false;
 	}
 
+	if (is_digit(operator[](0))) {
+		return false;
+	}
+
 	const char32_t *str = &operator[](0);
 
 	for (int i = 0; i < len; i++) {
-		if (!_is_valid_identifier_bit(i, str[i])) {
+		if (!is_ascii_identifier_char(str[i])) {
 			return false;
 		}
 	}
diff --git a/tests/core/string/test_string.h b/tests/core/string/test_string.h
index c10ad6e13d1..02349aedc0b 100644
--- a/tests/core/string/test_string.h
+++ b/tests/core/string/test_string.h
@@ -1716,7 +1716,7 @@ TEST_CASE("[String] validate_identifier") {
 	CHECK(empty_string.validate_identifier() == "_");
 
 	String numeric_only = "12345";
-	CHECK(numeric_only.validate_identifier() == "_2345");
+	CHECK(numeric_only.validate_identifier() == "_12345");
 
 	String name_with_spaces = "Name with spaces";
 	CHECK(name_with_spaces.validate_identifier() == "Name_with_spaces");