diff --git a/addons/im/im.py b/addons/im/im.py
index c47d0d9be7e..f1801fe7285 100644
--- a/addons/im/im.py
+++ b/addons/im/im.py
@@ -222,6 +222,13 @@ class im_session(osv.osv):
             }, context=context)
         return self.read(cr, uid, session_id, context=context)
 
+    def add_to_session(self, cr, uid, session_id, user_id, uuid=None, context=None):
+        my_id = self.pool.get("im.user").get_my_id(cr, uid, uuid, context=context)
+        session = self.read(cr, uid, session_id, context=context)
+        if my_id not in session.get("user_ids"):
+            raise Exception("Not allowed to modify a session when you are not in it.")
+        self.write(cr, uid, session_id, {"user_ids": [(4, user_id)]}, context=context)
+
 class im_user(osv.osv):
     _name = "im.user"
 
diff --git a/addons/im/static/src/js/im.js b/addons/im/static/src/js/im.js
index cad3c6dff0b..f26b8f5c4a2 100644
--- a/addons/im/static/src/js/im.js
+++ b/addons/im/static/src/js/im.js
@@ -70,7 +70,15 @@
 
             var self = this;
 
-            return this.c_manager.start_polling();
+            return this.c_manager.start_polling().then(function() {
+                self.c_manager.on("new_conversation", self, function(conv) {
+                    conv.$el.droppable({
+                        drop: function(event, ui) {
+                            self.add_user(conv, ui.draggable.data("user"));
+                        }
+                    });
+                });
+            });
         },
         calc_box: function() {
             var $topbar = instance.client.$(".oe_topbar");
@@ -133,6 +141,9 @@
                 self.c_manager.activate_session(session.id, true);
             });
         },
+        add_user: function(conversation, user) {
+            conversation.add_user(user);
+        },
     });
 
     instance.im.UserWidget = instance.web.Widget.extend({
@@ -146,6 +157,8 @@
             this.user.add_watcher();
         },
         start: function() {
+            this.$el.data("user", this.user);
+            this.$el.draggable({helper: "clone"});
             var change_status = function() {
                 this.$(".oe_im_user_online").toggle(this.user.get("im_status") === true);
             };
diff --git a/addons/im/static/src/js/im_common.js b/addons/im/static/src/js/im_common.js
index 6d88764b1d8..c5508a3b69a 100644
--- a/addons/im/static/src/js/im_common.js
+++ b/addons/im/static/src/js/im_common.js
@@ -223,6 +223,7 @@ function declare($, _, openerp) {
                     });
                     this.conversations.push(conv);
                     this.calc_positions();
+                    this.trigger("new_conversation", conv);
                 }, this));
             }
             if (focus) {
@@ -393,6 +394,19 @@ function declare($, _, openerp) {
         _go_bottom: function() {
             this.$(".oe_im_chatview_content").scrollTop($(this.$(".oe_im_chatview_content").children()[0]).height());
         },
+        add_user: function(user) {
+            if (user === this.me || _.contains(this.users, user))
+                return;
+            im_common.connection.model("im.session").call("add_to_session",
+                    [this.session_id, user.get("id"), this.c_manager.me.get("uuid")]).then(_.bind(function() {
+                if (_.contains(this.others, user)) {
+                    this.others = _.without(this.others, user);
+                } else {
+                    user.add_watcher();
+                }
+                this.users.push(user);
+            }, this));
+        },
         focus: function() {
             this.$(".oe_im_chatview_input").focus();
             if (! this.shown)