diff --git a/format.c b/format.c
index abd6808c..b3a63775 100644
--- a/format.c
+++ b/format.c
@@ -301,8 +301,9 @@ format_session(struct format_tree *ft, struct session *s)
 void
 format_client(struct format_tree *ft, struct client *c)
 {
-	char	*tim;
-	time_t	 t;
+	char		*tim;
+	time_t		 t;
+	struct session	*s;
 
 	format_add(ft, "client_cwd", "%s", c->cwd);
 	format_add(ft, "client_height", "%u", c->tty.sy);
@@ -333,6 +334,13 @@ format_client(struct format_tree *ft, struct client *c)
 		format_add(ft, "client_readonly", "%d", 1);
 	else
 		format_add(ft, "client_readonly", "%d", 0);
+
+	s = c->session;
+	if (s != NULL)
+		format_add(ft, "client_session", "%s", s->name);
+	s = c->last_session;
+	if (s != NULL && session_alive(s))
+		format_add(ft, "client_last_session", "%s", s->name);
 }
 
 /* Set default format keys for a winlink. */
diff --git a/tmux.1 b/tmux.1
index 15f93dd1..22ccb9a4 100644
--- a/tmux.1
+++ b/tmux.1
@@ -2968,8 +2968,10 @@ The following variables are available, where appropriate:
 .It Li "client_created_string" Ta "String time client created"
 .It Li "client_cwd" Ta "Working directory of client"
 .It Li "client_height" Ta "Height of client"
+.It Li "client_last_session" Ta "Name of the client's last session"
 .It Li "client_prefix" Ta "1 if prefix key has been pressed"
 .It Li "client_readonly" Ta "1 if client is readonly"
+.It Li "client_session" Ta "Name of the client's session"
 .It Li "client_termname" Ta "Terminal name of client"
 .It Li "client_tty" Ta "Pseudo terminal of client"
 .It Li "client_utf8" Ta "1 if client supports utf8"