diff --git a/Userland/Libraries/LibWeb/HTML/AttributeNames.h b/Userland/Libraries/LibWeb/HTML/AttributeNames.h
index 942df21e164..51b6d246794 100644
--- a/Userland/Libraries/LibWeb/HTML/AttributeNames.h
+++ b/Userland/Libraries/LibWeb/HTML/AttributeNames.h
@@ -250,6 +250,7 @@ namespace AttributeNames {
     __ENUMERATE_HTML_ATTRIBUTE(target)                     \
     __ENUMERATE_HTML_ATTRIBUTE(text)                       \
     __ENUMERATE_HTML_ATTRIBUTE(title)                      \
+    __ENUMERATE_HTML_ATTRIBUTE(truespeed)                  \
     __ENUMERATE_HTML_ATTRIBUTE(type)                       \
     __ENUMERATE_HTML_ATTRIBUTE(usemap)                     \
     __ENUMERATE_HTML_ATTRIBUTE(valign)                     \
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl
index 1403158097e..e67a79b4cbe 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl
@@ -14,7 +14,7 @@ interface HTMLMarqueeElement : HTMLElement {
     [FIXME, CEReactions] attribute long loop;
     [CEReactions] attribute unsigned long scrollAmount;
     [CEReactions] attribute unsigned long scrollDelay;
-    [FIXME, CEReactions] attribute boolean trueSpeed;
+    [CEReactions, Reflect=truespeed] attribute boolean trueSpeed;
     [CEReactions, Reflect] attribute unsigned long vspace;
     [CEReactions, Reflect] attribute DOMString width;