diff --git a/plugins/chat/lib/chat/types/array.rb b/plugins/chat/lib/chat/types/array.rb
new file mode 100644
index 00000000000..2c4672ff1b5
--- /dev/null
+++ b/plugins/chat/lib/chat/types/array.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module Chat
+  module Types
+    class Array < ActiveModel::Type::Value
+      def serializable?(_)
+        false
+      end
+
+      def cast_value(value)
+        case value
+        when String
+          value.split(",")
+        else
+          ::Array.wrap(value)
+        end
+      end
+    end
+  end
+end
diff --git a/plugins/chat/plugin.rb b/plugins/chat/plugin.rb
index 9f797d04800..2f0e17d373e 100644
--- a/plugins/chat/plugin.rb
+++ b/plugins/chat/plugin.rb
@@ -496,6 +496,8 @@ after_initialize do
   )
 
   register_bookmarkable(Chat::MessageBookmarkable)
+
+  ActiveModel::Type.register(:array, Chat::Types::Array)
 end
 
 if Rails.env == "test"
diff --git a/plugins/chat/spec/lib/chat/types/array_spec.rb b/plugins/chat/spec/lib/chat/types/array_spec.rb
new file mode 100644
index 00000000000..c6e843d4a18
--- /dev/null
+++ b/plugins/chat/spec/lib/chat/types/array_spec.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe Chat::Types::Array do
+  subject(:type) { described_class.new }
+
+  describe "#cast" do
+    subject(:casted_value) { type.cast(value) }
+
+    context "when 'value' is a string" do
+      let(:value) { "first,second,third" }
+
+      it "splits it" do
+        expect(casted_value).to eq(%w[first second third])
+      end
+    end
+
+    context "when 'value' is an array" do
+      let(:value) { %w[existing array] }
+
+      it "returns it" do
+        expect(casted_value).to eq(value)
+      end
+    end
+
+    context "when 'value' is something else" do
+      let(:value) { Time.current }
+
+      it "wraps it in a new array" do
+        expect(casted_value).to eq([value])
+      end
+    end
+  end
+end