diff --git a/starmath/Library_sm.mk b/starmath/Library_sm.mk
index a648b8c2bc1e..6aa75b31c061 100644
--- a/starmath/Library_sm.mk
+++ b/starmath/Library_sm.mk
@@ -25,7 +25,7 @@ $(eval $(call gb_Library_add_defs,sm,\
 	-DSM_DLLIMPLEMENTATION \
 ))
 
-$(eval $(call gb_Library_use_external,sm,boost_headers))
+$(eval $(call gb_Library_use_external,sm,boost_headers,icu_headers))
 
 $(eval $(call gb_Library_use_custom_headers,sm,\
 	officecfg/registry \