diff --git a/format.c b/format.c
index 2ebfe588..1dba66a6 100644
--- a/format.c
+++ b/format.c
@@ -1616,9 +1616,13 @@ format_cb_client_user(struct format_tree *ft)
 	struct passwd	*pw;
 
 	if (ft->c != NULL) {
+		if (ft->c->user != NULL)
+			return (xstrdup(ft->c->user));
 		uid = proc_get_peer_uid(ft->c->peer);
-		if (uid != (uid_t)-1 && (pw = getpwuid(uid)) != NULL)
-			return (xstrdup(pw->pw_name));
+		if (uid != (uid_t)-1 && (pw = getpwuid(uid)) != NULL) {
+			ft->c->user = xstrdup(pw->pw_name);
+			return (xstrdup(ft->c->user));
+		}
 	}
 	return (NULL);
 }
@@ -3076,10 +3080,13 @@ format_cb_uid(__unused struct format_tree *ft)
 static void *
 format_cb_user(__unused struct format_tree *ft)
 {
+	static char	*cached;
 	struct passwd	*pw;
 
-	if ((pw = getpwuid(getuid())) != NULL)
-		return (xstrdup(pw->pw_name));
+	if (cached == NULL && (pw = getpwuid(getuid())) != NULL)
+		cached = xstrdup(pw->pw_name);
+	if (cached != NULL)
+		return (xstrdup(cached));
 	return (NULL);
 }
 
diff --git a/server-client.c b/server-client.c
index 88de60d0..d6a6159e 100644
--- a/server-client.c
+++ b/server-client.c
@@ -537,6 +537,7 @@ server_client_free(__unused int fd, __unused short events, void *arg)
 
 	if (c->references == 0) {
 		free((void *)c->name);
+		free((void *)c->user);
 		free(c);
 	}
 }
diff --git a/tmux.h b/tmux.h
index 27f016de..87bcac78 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1958,6 +1958,7 @@ typedef void (*overlay_resize_cb)(struct client *, void *);
 struct client {
 	const char		*name;
 	struct tmuxpeer		*peer;
+	const char		*user;
 	struct cmdq_list	*queue;
 
 	struct client_windows	 windows;