diff --git a/router/src/mysql_protocol/include/mysqlrouter/classic_protocol_codec_message.h b/router/src/mysql_protocol/include/mysqlrouter/classic_protocol_codec_message.h
index 0acd70b21bb2..8f55018faf7d 100644
--- a/router/src/mysql_protocol/include/mysqlrouter/classic_protocol_codec_message.h
+++ b/router/src/mysql_protocol/include/mysqlrouter/classic_protocol_codec_message.h
@@ -2106,7 +2106,7 @@ class Codec<borrowable::message::client::StmtExecute<Borrowed>>
     if (!accu.result()) return stdx::make_unexpected(accu.result().error());
 
     std::vector<classic_protocol::field_type::value_type> types;
-    std::vector<std::optional<std::string>> values;
+    std::vector<std::optional<typename value_type::string_type>> values;
 
     if (new_params_bound_res->value()) {
       const auto nullbits = nullbits_res->value();
diff --git a/router/src/mysql_protocol/include/mysqlrouter/classic_protocol_message.h b/router/src/mysql_protocol/include/mysqlrouter/classic_protocol_message.h
index 39ece6ed1a7a..3a6689ce3ad1 100644
--- a/router/src/mysql_protocol/include/mysqlrouter/classic_protocol_message.h
+++ b/router/src/mysql_protocol/include/mysqlrouter/classic_protocol_message.h
@@ -1054,7 +1054,7 @@ class StmtExecute {
   using string_type =
       std::conditional_t<Borrowed, std::string_view, std::string>;
 
-  using value_type = std::optional<std::string>;
+  using value_type = std::optional<string_type>;
 
   /**
    * construct a ExecuteStmt message.