diff --git a/Gemfile b/Gemfile
index e43b1d049..5ecea1b88 100644
--- a/Gemfile
+++ b/Gemfile
@@ -13,7 +13,7 @@ gem "govspeak"
 gem "govuk_ab_testing"
 gem "govuk_app_config"
 gem "govuk_document_types"
-gem "govuk_publishing_components"
+gem "govuk_publishing_components", git: "https://github.com/alphagov/govuk_publishing_components.git", branch: "spike-font-size-changes-2"
 gem "plek"
 gem "rails-i18n"
 gem "rails_translation_manager"
diff --git a/Gemfile.lock b/Gemfile.lock
index f9453146c..eb4c6aadd 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,3 +1,18 @@
+GIT
+  remote: https://github.com/alphagov/govuk_publishing_components.git
+  revision: 5d08598e76673d55d0f2e899055bc04b6176db2b
+  branch: spike-font-size-changes-2
+  specs:
+    govuk_publishing_components (38.0.1)
+      govuk_app_config
+      govuk_personalisation (>= 0.7.0)
+      kramdown
+      plek
+      rails (>= 6)
+      rouge
+      sprockets (>= 3)
+      sprockets-rails
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -213,15 +228,6 @@ GEM
     govuk_personalisation (0.16.0)
       plek (>= 1.9.0)
       rails (>= 6, < 8)
-    govuk_publishing_components (38.0.1)
-      govuk_app_config
-      govuk_personalisation (>= 0.7.0)
-      kramdown
-      plek
-      rails (>= 6)
-      rouge
-      sprockets (>= 3)
-      sprockets-rails
     govuk_schemas (5.0.0)
       json-schema (>= 2.8, < 4.4)
     govuk_test (4.0.2)
@@ -281,7 +287,7 @@ GEM
       mime-types-data (~> 3.2015)
     mime-types-data (3.2024.0305)
     mini_mime (1.1.5)
-    mini_portile2 (2.8.5)
+    mini_portile2 (2.8.6)
     minitest (5.22.3)
     mocha (2.2.0)
       ruby2_keywords (>= 0.0.5)
@@ -614,7 +620,7 @@ GEM
     rdoc (6.6.3.1)
       psych (>= 4.0.0)
     regexp_parser (2.9.0)
-    reline (0.5.1)
+    reline (0.5.2)
       io-console (~> 0.5)
     request_store (1.6.0)
       rack (>= 1.4)
@@ -697,10 +703,10 @@ GEM
       rexml (~> 3.2, >= 3.2.5)
       rubyzip (>= 1.2.2, < 3.0)
       websocket (~> 1.0)
-    sentry-rails (5.17.2)
+    sentry-rails (5.17.3)
       railties (>= 5.0)
-      sentry-ruby (~> 5.17.2)
-    sentry-ruby (5.17.2)
+      sentry-ruby (~> 5.17.3)
+    sentry-ruby (5.17.3)
       bigdecimal
       concurrent-ruby (~> 1.0, >= 1.0.2)
     simplecov (0.22.0)
@@ -781,7 +787,7 @@ DEPENDENCIES
   govuk_ab_testing
   govuk_app_config
   govuk_document_types
-  govuk_publishing_components
+  govuk_publishing_components!
   govuk_schemas
   govuk_test
   i18n-coverage