diff --git a/specification/app/resource-manager/Microsoft.App/preview/2023-04-01-preview/CommonDefinitions.json b/specification/app/resource-manager/Microsoft.App/preview/2023-04-01-preview/CommonDefinitions.json
index ddd9468c54ee..134788350c0e 100644
--- a/specification/app/resource-manager/Microsoft.App/preview/2023-04-01-preview/CommonDefinitions.json
+++ b/specification/app/resource-manager/Microsoft.App/preview/2023-04-01-preview/CommonDefinitions.json
@@ -578,6 +578,11 @@
           "description": "User friendly suffix that is appended to the revision name",
           "type": "string"
         },
+        "terminationGracePeriodSeconds": {
+          "description": "Optional duration in seconds the Container App Instance needs to terminate gracefully. Value must be non-negative integer. The value zero indicates stop immediately via the kill signal (no opportunity to shut down). If this value is nil, the default grace period will be used instead. Set this value longer than the expected cleanup time for your process. Defaults to 30 seconds.",
+          "format": "int64",
+          "type": "integer"
+        },
         "initContainers": {
           "description": "List of specialized containers that run before app containers.",
           "type": "array",