diff --git a/ell.c b/ell.c
index 850083c..af65e85 100644
--- a/ell.c
+++ b/ell.c
@@ -1053,10 +1053,8 @@ defn (fn_concatenate) {
 		}
 		buffer_append (&buf, args->value, args->len);
 	}
-	buffer_append_c (&buf, '\0');
-
 	bool ok = !(ctx->memory_failure |= buf.memory_failure)
-		&& check (ctx, (*result = new_string (buf.s, buf.len - 1)));
+		&& check (ctx, (*result = new_string (buf.s, buf.len)));
 	free (buf.s);
 	return ok;
 }