diff --git a/Userland/Libraries/LibWeb/DOM/Element.cpp b/Userland/Libraries/LibWeb/DOM/Element.cpp
index b9aa52fd81..8d3f00763c 100644
--- a/Userland/Libraries/LibWeb/DOM/Element.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Element.cpp
@@ -270,6 +270,12 @@ WebIDL::ExceptionOr<void> Element::set_attribute_ns(Optional<String> const& name
     return {};
 }
 
+// https://dom.spec.whatwg.org/#concept-element-attributes-append
+void Element::append_attribute(Attr& attribute)
+{
+    m_attributes->append_attribute(attribute);
+}
+
 // https://dom.spec.whatwg.org/#concept-element-attributes-set-value
 void Element::set_attribute_value(FlyString const& local_name, DeprecatedString const& value, Optional<FlyString> const& prefix, DeprecatedFlyString const& namespace_)
 {
diff --git a/Userland/Libraries/LibWeb/DOM/Element.h b/Userland/Libraries/LibWeb/DOM/Element.h
index db0477be01..d4c4eb4ce0 100644
--- a/Userland/Libraries/LibWeb/DOM/Element.h
+++ b/Userland/Libraries/LibWeb/DOM/Element.h
@@ -122,6 +122,8 @@ public:
     WebIDL::ExceptionOr<JS::GCPtr<Attr>> set_attribute_node(Attr&);
     WebIDL::ExceptionOr<JS::GCPtr<Attr>> set_attribute_node_ns(Attr&);
 
+    void append_attribute(Attr&);
+
     // FIXME: This should take a 'FlyString cosnt&'
     void remove_attribute(StringView name);