diff --git a/app/controllers/member/details_controller.rb b/app/controllers/member/details_controller.rb
index eff9fba53..14cc0c711 100644
--- a/app/controllers/member/details_controller.rb
+++ b/app/controllers/member/details_controller.rb
@@ -21,7 +21,7 @@ def update
 
     return render :edit unless @member.update(attrs)
 
-    attrs[:newsletter] ? subscribe_to_newsletter(@member) : unsubscribe_from_newsletter(@member)
+    @member.newsletter ? subscribe_to_newsletter(@member) : unsubscribe_from_newsletter(@member)
     redirect_to step2_member_path
   end
 
diff --git a/app/models/member.rb b/app/models/member.rb
index f68b6427c..b2a96dfa7 100644
--- a/app/models/member.rb
+++ b/app/models/member.rb
@@ -63,7 +63,9 @@ class Member < ApplicationRecord
 
   acts_as_taggable_on :skills
 
-  attr_accessor :attendance, :newsletter
+  attr_accessor :attendance
+
+  attribute :newsletter, :boolean
 
   def organiser?
     organised_chapters.present?
diff --git a/spec/controllers/member/details_controller_spec.rb b/spec/controllers/member/details_controller_spec.rb
index bb06347f6..d0db8a953 100644
--- a/spec/controllers/member/details_controller_spec.rb
+++ b/spec/controllers/member/details_controller_spec.rb
@@ -73,6 +73,54 @@
         expect(member.how_you_found_us_other_reason).to eq('From a colleague')
         expect(response).to redirect_to(step2_member_path)
       end
+
+      it 'subscribes to the newsletter when checked' do
+        patch :update, params: {
+          id: member.id,
+          member: {
+            how_you_found_us: 'social_media',
+            newsletter: 'true'
+          }
+        }
+
+        expect(mailing_list).to have_received(:subscribe)
+        expect(mailing_list).not_to have_received(:unsubscribe)
+      end
+
+      it 'unsubscribes from the newsletter when unchecked' do
+        patch :update, params: {
+          id: member.id,
+          member: {
+            how_you_found_us: 'social_media',
+            newsletter: 'false'
+          }
+        }
+
+        expect(mailing_list).to have_received(:unsubscribe)
+        expect(mailing_list).not_to have_received(:subscribe)
+      end
+    end
+
+    context 'with a validation failure' do
+      it 'keeps the newsletter checkbox checked when it was checked' do
+        patch :update, params: {
+          id: member.id,
+          member: { newsletter: 'true' }
+        }
+
+        expect(response.body).to include('You must select one option')
+        expect(response.body).to have_css('input#member_newsletter[checked]')
+      end
+
+      it 'keeps the newsletter checkbox unchecked when it was unchecked' do
+        patch :update, params: {
+          id: member.id,
+          member: { newsletter: 'false' }
+        }
+
+        expect(response.body).to include('You must select one option')
+        expect(response.body).to have_no_css('input#member_newsletter[checked]')
+      end
     end
 
     context 'when update fails (invalid data)' do