diff --git a/addons/calendar/models/calendar.py b/addons/calendar/models/calendar.py
index 0606aac6b36..16e99e1fe2d 100644
--- a/addons/calendar/models/calendar.py
+++ b/addons/calendar/models/calendar.py
@@ -528,6 +528,27 @@ class Meeting(models.Model):
     _order = "id desc"
     _inherit = ["mail.thread"]
 
+    @api.model
+    def default_get(self, fields):
+        if self.env.context.get('default_res_model'):  # super default_model='crm.lead' for easier use in adddons
+            self = self.with_context(
+                default_res_model_id=self.env['ir.model'].sudo().search([
+                    ('model', '=', self.env.context['default_res_model'])
+                ], limit=1).id
+            )
+
+        defaults = super(Meeting, self).default_get(fields)
+
+        # support active_model / active_id as replacement of default_* if not already given
+        if 'res_model_id' not in defaults and 'res_model_id' in fields and \
+                self.env.context.get('active_model') and self.env.context['active_model'] != 'calendar.event':
+            defaults['res_model_id'] = self.env['ir.model'].sudo().search([('model', '=', self.env.context['active_model'])], limit=1).id
+        if 'res_id' not in defaults and 'res_id' in fields and \
+                defaults.get('res_model_id') and self.env.context.get('active_id'):
+            defaults['res_id'] = self.env.context['active_id']
+
+        return defaults
+
     @api.model
     def _default_partners(self):
         """ When active_model is res.partner, the current partners should be attendees """
@@ -710,6 +731,11 @@ class Meeting(models.Model):
     location = fields.Char('Location', states={'done': [('readonly', True)]}, track_visibility='onchange', help="Location of Event")
     show_as = fields.Selection([('free', 'Free'), ('busy', 'Busy')], 'Show Time as', states={'done': [('readonly', True)]}, default='busy')
 
+    # linked document
+    res_id = fields.Integer('Document ID')
+    res_model_id = fields.Many2one('ir.model', 'Document Model', ondelete='cascade')
+    res_model = fields.Char('Document Model Name', related='res_model_id.model', readonly=True, store=True)
+
     # RECURRENCE FIELD
     rrule = fields.Char('Recurrent Rule', compute='_compute_rrule', inverse='_inverse_rrule', store=True)
     rrule_type = fields.Selection([
@@ -1277,6 +1303,12 @@ class Meeting(models.Model):
             'flags': {'form': {'action_buttons': True, 'options': {'mode': 'edit'}}}
         }
 
+    @api.multi
+    def action_open_calendar_event(self):
+        if self.res_model and self.res_id:
+            return self.env[self.res_model].browse(self.res_id).get_formview_action()
+        return False
+
     @api.multi
     def action_sendmail(self):
         email = self.env.user.email
diff --git a/addons/calendar/views/calendar_views.xml b/addons/calendar/views/calendar_views.xml
index d0857a179f2..eb7707af2d1 100644
--- a/addons/calendar/views/calendar_views.xml
+++ b/addons/calendar/views/calendar_views.xml
@@ -88,6 +88,9 @@
         <field name="arch" type="xml">
             <form string="Meetings">
                 <sheet>
+                    <button string="Document" class="oe_stat_button pull-right" icon="fa-bars" type="object" name="action_open_calendar_event" attrs="{'invisible': ['|', ('res_model', '=', False), ('res_id', '=', False)]}"/>
+                    <field name="res_model" invisible="1" />
+                    <field name="res_id" invisible="1" />
                     <field name="state" invisible="1"/>
                     <field name="is_attendee" invisible="1"/>
                     <field name="attendee_status" invisible="1"/>
@@ -233,6 +236,9 @@
         <field name="priority" eval="2"/>
         <field name="arch" type="xml">
             <form string="Meetings">
+                <button string="Document" class="oe_stat_button pull-right" icon="fa-bars" type="object" name="action_open_calendar_event" attrs="{'invisible': ['|', ('res_model', '=', False), ('res_id', '=', False)]}"/>
+                <field name="res_model" invisible="1" />
+                <field name="res_id" invisible="1" />
                 <field name="state" invisible="1"/>
                 <field name="is_attendee" invisible="1"/>
                 <field name="attendee_status" invisible="1"/>
diff --git a/addons/crm/models/calendar.py b/addons/crm/models/calendar.py
index e30fda1c847..f5c4466f245 100644
--- a/addons/crm/models/calendar.py
+++ b/addons/crm/models/calendar.py
@@ -8,6 +8,15 @@ class CalendarEvent(models.Model):
 
     _inherit = 'calendar.event'
 
+    @api.model
+    def default_get(self, fields):
+        defaults = super(CalendarEvent, self).default_get(fields)
+        if 'res_model_id' not in defaults and defaults.get('opportunity_id'):
+            defaults['res_model_id'] = self.env.ref('model_crm_lead').id
+        if 'res_id' not in defaults and defaults.get('opportunity_id'):
+            defaults['res_id'] = defaults['opportunity_id']
+        return defaults
+
     def _compute_is_highlighted(self):
         super(CalendarEvent, self)._compute_is_highlighted()
         if self.env.context.get('active_model') == 'crm.lead':
diff --git a/addons/hr_recruitment/models/calendar.py b/addons/hr_recruitment/models/calendar.py
index 0a2bbe04c86..379924c4597 100644
--- a/addons/hr_recruitment/models/calendar.py
+++ b/addons/hr_recruitment/models/calendar.py
@@ -8,6 +8,15 @@ class CalendarEvent(models.Model):
     """ Model for Calendar Event """
     _inherit = 'calendar.event'
 
+    @api.model
+    def default_get(self, fields):
+        defaults = super(CalendarEvent, self).default_get(fields)
+        if 'res_model_id' not in defaults and defaults.get('applicant_id'):
+            defaults['res_model_id'] = self.env.ref('model_hr_applicant').id
+        if 'res_id' not in defaults and defaults.get('applicant_id'):
+            defaults['res_id'] = defaults['applicant_id']
+        return defaults
+
     def _compute_is_highlighted(self):
         super(CalendarEvent, self)._compute_is_highlighted()
         applicant_id = self.env.context.get('active_id')