diff --git a/src/evalfunc.c b/src/evalfunc.c
index 21ed15e..125ba55 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -8632,6 +8632,9 @@
 	    else if (lv.ll_list != NULL)
 		// List item.
 		rettv->vval.v_number = tv_islocked(&lv.ll_li->li_tv);
+	    else if (lv.ll_tuple != NULL)
+		// Tuple item.
+		rettv->vval.v_number = tv_islocked(lv.ll_tv);
 	    else
 		// Dictionary item.
 		rettv->vval.v_number = tv_islocked(&lv.ll_di->di_tv);