diff --git a/src/mongo/db/query/collation/collator_interface_icu.h b/src/mongo/db/query/collation/collator_interface_icu.h
index 9bb8382..7607462 100644
--- a/src/mongo/db/query/collation/collator_interface_icu.h
+++ b/src/mongo/db/query/collation/collator_interface_icu.h
@@ -31,10 +31,7 @@
#include "mongo/db/query/collation/collator_interface.h"
#include <memory>
-
-namespace icu {
-class Collator;
-} // namespace icu
+#include <unicode/coll.h>
namespace mongo {