diff --git a/lib/missing.d.ts b/lib/missing.d.ts
index 7e22cc933e6f50..49393e12b3fe46 100644
--- a/lib/missing.d.ts
+++ b/lib/missing.d.ts
@@ -1,15 +1,3 @@
-declare module 'json-dup-key-validator' {
-  export function validate(
-    jsonString: string,
-    allowDuplicatedKeys?: boolean
-  ): string | undefined;
-
-  export function parse<T = unknown>(
-    jsonString: string,
-    allowDuplicatedKeys?: boolean
-  ): T;
-}
-
 declare module 'changelog-filename-regex' {
   const re: RegExp;
   export = re;
diff --git a/package.json b/package.json
index bd9fae2ddbd06d..6532a7305773bf 100644
--- a/package.json
+++ b/package.json
@@ -202,6 +202,7 @@
     "@types/ini": "1.3.30",
     "@types/jest": "26.0.3",
     "@types/js-yaml": "3.12.4",
+    "@types/json-dup-key-validator": "1.0.0",
     "@types/json5": "0.0.30",
     "@types/later": "1.2.6",
     "@types/lodash": "4.14.157",
diff --git a/yarn.lock b/yarn.lock
index 287fb1124cc1ce..654696d73335bd 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1592,6 +1592,11 @@
   resolved "https://registry.yarnpkg.com/@types/js-yaml/-/js-yaml-3.12.4.tgz#7d3b534ec35a0585128e2d332db1403ebe057e25"
   integrity sha512-fYMgzN+9e28R81weVN49inn/u798ruU91En1ZnGvSZzCRc5jXx9B2EDhlRaWmcO1RIxFHL8AajRXzxDuJu93+A==
 
+"@types/json-dup-key-validator@1.0.0":
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/@types/json-dup-key-validator/-/json-dup-key-validator-1.0.0.tgz#3a666ab980e5e957960e9341e13eabd4fd9a24f3"
+  integrity sha512-D/pvJeKintUSW4G+aBRSvReECxCHbMcE9IuSU7cfWQAtYStE/vH8OLXFw38JJ37dSEnpcOkEV7q4WmdvtV0zHg==
+
 "@types/json-schema@*", "@types/json-schema@^7.0.3":
   version "7.0.5"
   resolved "https://registry.yarnpkg.com/@types/json-schema/-/json-schema-7.0.5.tgz#dcce4430e64b443ba8945f0290fb564ad5bac6dd"