diff --git a/src/bot.coffee b/src/bot.coffee
index 65b5a89f..1cac6dd1 100644
--- a/src/bot.coffee
+++ b/src/bot.coffee
@@ -272,13 +272,17 @@ class SlackBot extends Adapter
       # this event type always has a channel
       user.room = channel
       @robot.logger.debug "Received enter message for user: #{user.id}, joining: #{channel}"
-      @receive new EnterMessage user
+      msg = new EnterMessage user
+      msg.ts = event.ts
+      @receive msg
 
     else if event.type is "member_left_channel"
       # this event type always has a channel
       user.room = channel
       @robot.logger.debug "Received leave message for user: #{user.id}, joining: #{channel}"
-      @receive new LeaveMessage user
+      msg = new LeaveMessage user
+      msg.ts = event.ts
+      @receive msg
 
     else if event.type is "reaction_added" or event.type is "reaction_removed"
 
diff --git a/test/bot.coffee b/test/bot.coffee
index 8e688d60..adb5e413 100644
--- a/test/bot.coffee
+++ b/test/bot.coffee
@@ -223,13 +223,23 @@ describe 'Handling incoming messages', ->
     return
 
   it 'Should handle member_joined_channel events as envisioned', ->
-    @slackbot.eventHandler {type: 'member_joined_channel', user: @stubs.user, channel: @stubs.channel.id}
+    @slackbot.eventHandler
+      type: 'member_joined_channel'
+      user: @stubs.user
+      channel: @stubs.channel.id
+      ts: @stubs.event_timestamp
     should.equal @stubs._received.constructor.name, "EnterMessage"
+    should.equal @stubs._received.ts, @stubs.event_timestamp
     @stubs._received.user.id.should.equal @stubs.user.id
 
   it 'Should handle member_left_channel events as envisioned', ->
-    @slackbot.eventHandler {type: 'member_left_channel', user: @stubs.user, channel: @stubs.channel.id}
+    @slackbot.eventHandler
+      type: 'member_left_channel'
+      user: @stubs.user
+      channel: @stubs.channel.id
+      ts: @stubs.event_timestamp
     should.equal @stubs._received.constructor.name, "LeaveMessage"
+    should.equal @stubs._received.ts, @stubs.event_timestamp
     @stubs._received.user.id.should.equal @stubs.user.id
 
   it 'Should handle channel_topic events as envisioned', ->
diff --git a/test/stubs.coffee b/test/stubs.coffee
index 5e889da9..29ba8491 100644
--- a/test/stubs.coffee
+++ b/test/stubs.coffee
@@ -112,6 +112,7 @@ beforeEach ->
     name: 'Example Team'
     id: 'T123'
   @stubs.expired_timestamp = 1528238205453
+  @stubs.event_timestamp = '1360782804.083113'
 
   # Slack client
   @stubs.client =