diff --git a/libraries/botframework-expressions/package.json b/libraries/botframework-expressions/package.json
index cf79acdf05..e36cd7d2ae 100644
--- a/libraries/botframework-expressions/package.json
+++ b/libraries/botframework-expressions/package.json
@@ -15,6 +15,7 @@
   "main": "./lib/index.js",
   "typings": "./lib/index.d.ts",
   "dependencies": {
+    "@types/lru-cache": "^5.1.0",
     "@microsoft/recognizers-text-data-types-timex-expression": "^1.1.4",
     "antlr4ts": "0.5.0-alpha.1",
     "jspath": "^0.4.0",