diff --git a/.changeset/nine-taxis-study.md b/.changeset/nine-taxis-study.md
new file mode 100644
index 0000000000..693534c2be
--- /dev/null
+++ b/.changeset/nine-taxis-study.md
@@ -0,0 +1,5 @@
+---
+'@backstage/core-components': patch
+---
+
+Minor internal tweak to handle `classnames` update
diff --git a/packages/core-components/src/layout/Sidebar/Items.tsx b/packages/core-components/src/layout/Sidebar/Items.tsx
index 715e0d4af7..c40d45f8b4 100644
--- a/packages/core-components/src/layout/Sidebar/Items.tsx
+++ b/packages/core-components/src/layout/Sidebar/Items.tsx
@@ -351,7 +351,7 @@ export const WorkaroundNavLink = React.forwardRef<
       aria-current={ariaCurrent}
       style={{ ...style, ...(isActive ? activeStyle : undefined) }}
       className={classnames([
-        className,
+        typeof className !== 'function' ? className : undefined,
         isActive ? activeClassName : undefined,
       ])}
     />