diff --git a/include/seastar/core/sstring.hh b/include/seastar/core/sstring.hh
index ff352294cc0..8ad45d772fc 100644
--- a/include/seastar/core/sstring.hh
+++ b/include/seastar/core/sstring.hh
@@ -37,6 +37,7 @@
 #include <ostream>
 #include <functional>
 #include <type_traits>
+#include <fmt/format.h>
 #include <fmt/ostream.h>
 #endif
 #include <seastar/util/std-compat.hh>