diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index 13c37b5787..88be52e22a 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -2820,10 +2820,11 @@ peer_update_source_vty (struct vty *vty, const char *peer_str,
   return CMD_SUCCESS;
 }
 
-#define BGP_UPDATE_SOURCE_STR "(A.B.C.D|X:X::X:X)"
+#define BGP_UPDATE_SOURCE_STR "(A.B.C.D|X:X::X:X|WORD)"
 #define BGP_UPDATE_SOURCE_HELP_STR \
   "IPv4 address\n" \
-  "IPv6 address\n"
+  "IPv6 address\n" \
+  "Interface name (requires zebra to be running)\n"
 
 DEFUN (neighbor_update_source,
        neighbor_update_source_cmd,