diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index 315cbf2684..7512b02d18 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -3277,7 +3277,13 @@ ParserBase<Impl>::ParseLeftHandSideContinuation(ExpressionT result) {
         if (is_optional) {
           DCHECK_EQ(scanner()->current_token(), Token::QUESTION_PERIOD);
           int pos = position();
-          ExpressionT key = ParsePropertyOrPrivatePropertyName();
+          Token::Value next = Next();
+          if (V8_UNLIKELY(!Token::IsPropertyName(next))) {
+            ReportUnexpectedToken(next);
+            return impl()->FailureExpression();
+          }
+          IdentifierT name = impl()->GetSymbol();
+          ExpressionT key = factory()->NewStringLiteral(name, position());
           result = factory()->NewProperty(result, key, pos, is_optional);
           break;
         }
diff --git a/test/mjsunit/harmony/optional-chaining.js b/test/mjsunit/harmony/optional-chaining.js
index 72b0559e00..a6121f5fcb 100644
--- a/test/mjsunit/harmony/optional-chaining.js
+++ b/test/mjsunit/harmony/optional-chaining.js
@@ -101,6 +101,7 @@ shouldThrowSyntaxError('function foo() { new?.target; }');
 
 shouldThrowSyntaxError('function tag() {} tag?.``;');
 shouldThrowSyntaxError('const o = { tag() {} }; o?.tag``;');
+shouldThrowSyntaxError('class A { #foo = "hi"; constructor() { this?.#foo; } }')
 
 const o2 = {
   count: 0,