diff --git a/config/routes.rb b/config/routes.rb
index cc638f20855..49402b58b08 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -326,7 +326,7 @@ Discourse::Application.routes.draw do
   get "users/:username/messages/group/:group_name/archive" => "user_actions#private_messages", constraints: {username: USERNAME_ROUTE_FORMAT, group_name: USERNAME_ROUTE_FORMAT}
 
   get "users/:username.json" => "users#show", constraints: {username: USERNAME_ROUTE_FORMAT}, defaults: {format: :json}
-  get "users/:username" => "users#show", as: 'user', constraints: {username: USERNAME_ROUTE_FORMAT}
+  get "users/:username" => "users#show", as: 'user', constraints: {username: USERNAME_ROUTE_FORMAT, format: /(json|html)/}
   put "users/:username" => "users#update", constraints: {username: USERNAME_ROUTE_FORMAT}, defaults: { format: :json }
   get "users/:username/emails" => "users#check_emails", constraints: {username: USERNAME_ROUTE_FORMAT}
   get "users/:username/preferences" => "users#preferences", constraints: {username: USERNAME_ROUTE_FORMAT}, as: :email_preferences
diff --git a/spec/integration/users_spec.rb b/spec/integration/users_spec.rb
index aed127a1a1a..7350c87ca5f 100644
--- a/spec/integration/users_spec.rb
+++ b/spec/integration/users_spec.rb
@@ -3,6 +3,29 @@ require 'rails_helper'
 RSpec.describe "Users" do
   let(:user) { Fabricate(:user) }
 
+  describe "viewing a user" do
+
+    it "should be able to view a user" do
+      get "/users/#{user.username}"
+
+      expect(response).to be_success
+      expect(response.body).to include(user.username)
+    end
+
+    describe 'when username contains a period' do
+      before do
+        user.update!(username: 'test.test')
+      end
+
+      it "should be able to view a user" do
+        get "/users/#{user.username}"
+
+        expect(response).to be_success
+        expect(response.body).to include(user.username)
+      end
+    end
+  end
+
   describe "updating a user" do
     before do
       sign_in(user)