diff --git a/app/models/user.rb b/app/models/user.rb
index 07d1bbe..855fd0d 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -33,7 +33,8 @@ class User < ApplicationRecord
   validates_uniqueness_of :email
   validates :email, email: true
 
-  validates_length_of :display_name, minimum: 3, maximum: 35, allow_blank: true
+  validates_length_of :display_name, minimum: 3, maximum: 35, allow_blank: true,
+                                     if: -> { defined?(@display_name) }
 
   scope :confirmed, -> { where.not(confirmed_at: nil) }
   scope :pending,   -> { where(confirmed_at: nil) }