diff --git a/tmux.h b/tmux.h
index 58899680..2fdf7eb6 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1695,6 +1695,7 @@ struct client {
 
 	char		*prompt_string;
 	struct utf8_data *prompt_buffer;
+	char		*prompt_last;
 	size_t		 prompt_index;
 	prompt_input_cb	 prompt_inputcb;
 	prompt_free_cb	 prompt_freecb;