diff --git a/src/helpers.ts b/src/helpers.ts
index 050770e..e15de92 100644
--- a/src/helpers.ts
+++ b/src/helpers.ts
@@ -31,7 +31,8 @@ export function translateEnvVariables() {
   ];
   for (const envVar of envVars) {
     if (process.env[envVar]) {
-      process.env[`INPUT_${envVar.replace(/_/g, '-')}`] = process.env[envVar];
+      const inputKey = `INPUT_${envVar.replace(/_/g, '-')}`;
+      process.env[inputKey] = process.env[inputKey] || process.env[envVar];
     }
   }
 }