diff --git a/src/catch2/internal/catch_stream.cpp b/src/catch2/internal/catch_stream.cpp
index ec1179d3..1a723aad 100644
--- a/src/catch2/internal/catch_stream.cpp
+++ b/src/catch2/internal/catch_stream.cpp
@@ -173,10 +173,14 @@ namespace Detail {
         Singleton<StringStreams>::getMutable().release( m_index );
     }
 
-    auto ReusableStringStream::str() const -> std::string {
+    std::string ReusableStringStream::str() const {
         return static_cast<std::ostringstream*>( m_oss )->str();
     }
 
+    void ReusableStringStream::str( std::string const& str ) {
+        static_cast<std::ostringstream*>( m_oss )->str( str );
+    }
+
 
     ///////////////////////////////////////////////////////////////////////////
 
diff --git a/src/catch2/internal/catch_stream.hpp b/src/catch2/internal/catch_stream.hpp
index 557797ae..51d32e62 100644
--- a/src/catch2/internal/catch_stream.hpp
+++ b/src/catch2/internal/catch_stream.hpp
@@ -37,7 +37,10 @@ namespace Catch {
         ReusableStringStream();
         ~ReusableStringStream();
 
-        auto str() const -> std::string;
+        //! Returns the serialized state
+        std::string str() const;
+        //! Sets internal state to `str`
+        void str(std::string const& str);
 
 #if defined(__GNUC__) && !defined(__clang__)
 #pragma GCC diagnostic push