diff --git a/app/controllers/topics_controller.rb b/app/controllers/topics_controller.rb
index 53c07e6d18e..0c976495578 100644
--- a/app/controllers/topics_controller.rb
+++ b/app/controllers/topics_controller.rb
@@ -190,12 +190,20 @@ class TopicsController < ApplicationController
   end
 
   def invite
-    params.require(:user)
+    username_or_email = params[:user]
+    if username_or_email
+      # provides a level of protection for hashes
+      params.require(:user)
+    else
+      params.require(:email)
+      username_or_email = params[:email]
+    end
+
     topic = Topic.where(id: params[:topic_id]).first
     guardian.ensure_can_invite_to!(topic)
 
-    if topic.invite(current_user, params[:user])
-      user = User.find_by_username_or_email(params[:user])
+    if topic.invite(current_user, username_or_email)
+      user = User.find_by_username_or_email(username_or_email)
       if user
         render_json_dump BasicUserSerializer.new(user, scope: guardian, root: 'user')
       else
diff --git a/app/models/invite_redeemer.rb b/app/models/invite_redeemer.rb
index 5e7f51fd409..91fb3aefad7 100644
--- a/app/models/invite_redeemer.rb
+++ b/app/models/invite_redeemer.rb
@@ -18,6 +18,7 @@ InviteRedeemer = Struct.new(:invite) do
     add_to_private_topics_if_invited
     add_user_to_invited_topics
     send_welcome_message
+    approve_account_if_needed
     notify_invitee
   end
 
@@ -66,8 +67,12 @@ InviteRedeemer = Struct.new(:invite) do
     end
   end
 
+  def approve_account_if_needed
+    invited_user.approve(invite.invited_by_id, send_email=false)
+  end
+
   def notify_invitee
     invite.invited_by.notifications.create(notification_type: Notification.types[:invitee_accepted],
                                            data: {display_username: invited_user.username}.to_json)
   end
-end
\ No newline at end of file
+end
diff --git a/app/models/user.rb b/app/models/user.rb
index aae321eb6ee..77eddf65609 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -182,7 +182,13 @@ class User < ActiveRecord::Base
   # Approve this user
   def approve(approved_by, send_mail=true)
     self.approved = true
-    self.approved_by = approved_by
+
+    if Fixnum === approved_by
+      self.approved_by_id = approved_by
+    else
+      self.approved_by = approved_by
+    end
+
     self.approved_at = Time.now
 
     send_approval_email if save and send_mail
diff --git a/lib/current_user.rb b/lib/current_user.rb
index d909e5d1fb5..4b204726cc0 100644
--- a/lib/current_user.rb
+++ b/lib/current_user.rb
@@ -59,9 +59,9 @@ module CurrentUser
       @current_user.update_ip_address!(request.remote_ip)
     end
 
-    # possible we have an api call, impersonate 
+    # possible we have an api call, impersonate
     unless @current_user
-      if api_key = request["api_key"] 
+      if api_key = request["api_key"]
         if api_username = request["api_username"]
           if SiteSetting.api_key_valid?(api_key)
             @current_user = User.where(username_lower: api_username.downcase).first
diff --git a/spec/models/invite_spec.rb b/spec/models/invite_spec.rb
index 55154b00cfc..727914e287e 100644
--- a/spec/models/invite_spec.rb
+++ b/spec/models/invite_spec.rb
@@ -172,19 +172,22 @@ describe Invite do
 
     end
 
+    context 'inviting when must_approve_users? is enabled' do
+      it 'correctly acitvates accounts' do
+        SiteSetting.stubs(:must_approve_users).returns(true)
+        user = invite.redeem
+
+        user.approved?.should == true
+      end
+    end
+
     context 'simple invite' do
 
       let!(:user) { invite.redeem }
 
-      it 'returns a user record' do
+      it 'works correctly' do
         user.is_a?(User).should be_true
-      end
-
-      it 'wants us to send a welcome message' do
         user.send_welcome_message.should be_true
-      end
-
-      it 'has the default_invitee_trust_level' do
         user.trust_level.should == SiteSetting.default_invitee_trust_level
       end
 
@@ -193,28 +196,24 @@ describe Invite do
           invite.reload
         end
 
-        it 'no longer in the pending list for that user' do
+        it 'works correctly' do
+          # no longer in the pending list for that user
           InvitedList.new(invite.invited_by).pending.should be_blank
-        end
 
-        it 'is redeeemed in the invite list for the creator' do
+          # is redeeemed in the invite list for the creator
           InvitedList.new(invite.invited_by).redeemed.should == [invite]
-        end
 
-        it 'has set the user_id attribute' do
+          # has set the user_id attribute
           invite.user.should == user
-        end
 
-        it 'returns true for redeemed' do
+          # returns true for redeemed
           invite.should be_redeemed
         end
 
+
         context 'again' do
           it 'will not redeem twice' do
             invite.redeem.should == user
-          end
-
-          it "doesn't want us to send a welcome message" do
             invite.redeem.send_welcome_message.should be_false
           end