diff --git a/lib/tasks/deployment/20210322124720_backfill_experts_procedure_id_missing_on_avis.rake b/lib/tasks/deployment/20210322124720_backfill_experts_procedure_id_missing_on_avis.rake
new file mode 100644
index 000000000..65c096b81
--- /dev/null
+++ b/lib/tasks/deployment/20210322124720_backfill_experts_procedure_id_missing_on_avis.rake
@@ -0,0 +1,38 @@
+namespace :after_party do
+  desc 'Deployment task: backfill_experts_procedure_id_missing_on_avis'
+  task backfill_experts_procedure_id_missing_on_avis: :environment do
+    puts "Running deploy task 'backfill_experts_procedure_id_missing_on_avis'"
+
+    without_instructeur = Avis.where(experts_procedure_id: nil, answer: nil, instructeur_id: nil).where.not(email: nil)
+    with_instructeur = Avis.where(experts_procedure_id: nil, answer: nil, email: nil).where.not(instructeur_id: nil)
+    progress = ProgressReport.new(without_instructeur.count)
+    progress2 = ProgressReport.new(with_instructeur.count)
+
+    without_instructeur.find_each do |avis|
+      # if the avis email is valid then we create the associated expert
+      if Devise.email_regexp.match?(avis.email)
+        user = User.create_or_promote_to_expert(avis.email, SecureRandom.hex)
+        user.reload
+        experts_procedure = ExpertsProcedure.find_or_create_by(procedure: avis.dossier.procedure, expert: user.expert)
+        avis.update_column(:experts_procedure_id, experts_procedure.id)
+      end
+      progress.inc
+    end
+    progress.finish
+
+    with_instructeur.find_each do |avis|
+      instructeur = avis.instructeur
+      if instructeur && instructeur.user
+        user = User.create_or_promote_to_expert(instructeur.user.email, SecureRandom.hex)
+        user.reload
+        experts_procedure = ExpertsProcedure.find_or_create_by(procedure: avis.dossier.procedure, expert: user.expert)
+        avis.update_column(:experts_procedure_id, experts_procedure.id)
+      end
+      progress2.inc
+    end
+    progress2.finish
+
+    AfterParty::TaskRecord
+      .create version: AfterParty::TaskRecorder.new(__FILE__).timestamp
+  end
+end