diff --git a/addons/mail/models/mail_channel.py b/addons/mail/models/mail_channel.py
index 737028949ea..4edea5edede 100644
--- a/addons/mail/models/mail_channel.py
+++ b/addons/mail/models/mail_channel.py
@@ -1191,11 +1191,11 @@ class Channel(models.Model):
     def execute_command_help(self, **kwargs):
         partner = self.env.user.partner_id
         if self.channel_type == 'channel':
-            msg = _("You are in channel <b>#%s</b>.", self.name)
+            msg = _("You are in channel <b>#%s</b>.", html_escape(self.name))
         else:
             all_channel_members = self.env['mail.channel.member'].with_context(active_test=False)
             channel_members = all_channel_members.search([('partner_id', '!=', partner.id), ('channel_id', '=', self.id)])
-            msg = _("You are in a private conversation with <b>@%s</b>.", html_escape(channel_members[0].partner_id.name if channel_members else _("Anonymous")))
+            msg = _("You are in a private conversation with <b>@%s</b>.", _(" @").join(html_escape(member.partner_id.name) for member in channel_members) if channel_members else _("Anonymous"))
         msg += self._execute_command_help_message_extra()
 
         self._send_transient_message(partner, msg)