diff --git a/CHANGELOG.md b/CHANGELOG.md
index cccc2700ab..ad122ff570 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@
   useful summary for people upgrading their application, not a replication
   of the commit log.
 
+## Unreleased
+
+* Add `ostruct` as an explicit dependency ([PR #4251](https://github.com/alphagov/govuk_publishing_components/pull/4251))
+
 ## 43.4.1
 
 * Add accessible-autocomplete node_modules to gemspec ([PR #4246](https://github.com/alphagov/govuk_publishing_components/pull/4246))
diff --git a/Gemfile.lock b/Gemfile.lock
index 2ecc86f147..582bbbf6e1 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -5,6 +5,7 @@ PATH
       govuk_app_config
       govuk_personalisation (>= 0.7.0)
       kramdown
+      ostruct
       plek
       rails (>= 6)
       rouge
@@ -423,6 +424,7 @@ GEM
       opentelemetry-semantic_conventions
     opentelemetry-semantic_conventions (1.10.1)
       opentelemetry-api (~> 1.0)
+    ostruct (0.6.0)
     parallel (1.25.1)
     parser (3.3.3.0)
       ast (~> 2.4.1)
diff --git a/govuk_publishing_components.gemspec b/govuk_publishing_components.gemspec
index 916e902e00..5ba588b936 100644
--- a/govuk_publishing_components.gemspec
+++ b/govuk_publishing_components.gemspec
@@ -19,6 +19,7 @@ Gem::Specification.new do |s|
   s.add_dependency "govuk_app_config"
   s.add_dependency "govuk_personalisation", ">= 0.7.0"
   s.add_dependency "kramdown"
+  s.add_dependency "ostruct"
   s.add_dependency "plek"
   s.add_dependency "rails", ">= 6"
   s.add_dependency "rouge"