diff --git a/include/wx/string.h b/include/wx/string.h
index 6a47d751a0..3890dd07d1 100644
--- a/include/wx/string.h
+++ b/include/wx/string.h
@@ -1154,7 +1154,11 @@ public:
     static wxString FromUTF8(const char *utf8)
       { return wxString(wxConvUTF8.cMB2WC(utf8)); }
     static wxString FromUTF8(const char *utf8, size_t len)
-      { return wxString(wxConvUTF8.cMB2WC(utf8, len == npos ? wxNO_LEN : len)); }
+    {
+      size_t wlen;
+      wxWCharBuffer buf(wxConvUTF8.cMB2WC(utf8, len == npos ? wxNO_LEN : len, &wlen));
+      return wxString(buf.data(), wlen);
+    }
     const wxCharBuffer utf8_str() const { return wxConvUTF8.cWC2MB(wc_str()); }
     const wxCharBuffer ToUTF8() const { return utf8_str(); }
 #endif