diff --git a/.chronus/changes/alexbat-delegatedIdentityClientId-1-2024-2-26-22-1-56.md b/.chronus/changes/alexbat-delegatedIdentityClientId-1-2024-2-26-22-1-56.md
new file mode 100644
index 0000000000..347947fe9f
--- /dev/null
+++ b/.chronus/changes/alexbat-delegatedIdentityClientId-1-2024-2-26-22-1-56.md
@@ -0,0 +1,7 @@
+---
+changeKind: feature
+packages:
+  - "@azure-tools/typespec-azure-resource-manager"
+---
+
+Made `delegatedIdentityClientId` optional `CustomerManagedKeyEncryption` to align with the common types definition.
diff --git a/docs/libraries/azure-resource-manager/reference/data-types.md b/docs/libraries/azure-resource-manager/reference/data-types.md
index 3dee2d81bc..239214242c 100644
--- a/docs/libraries/azure-resource-manager/reference/data-types.md
+++ b/docs/libraries/azure-resource-manager/reference/data-types.md
@@ -392,7 +392,7 @@ model Azure.ResourceManager.CustomerManagedKeyEncryption
 | keyEncryptionIdentity?          | [`KeyEncryptionIdentity`](./data-types.md#Azure.ResourceManager.KeyEncryptionIdentity) | The type of identity to use. Values can be systemAssignedIdentity, userAssignedIdentity, or delegatedResourceIdentity.                                                                                                                                                                                                             |
 | userAssignedIdentityResourceId? | [`ResourceIdentifier`](#Azure.ResourceManager.ResourceIdentifier)                      | User assigned identity to use for accessing key encryption key Url. Ex: /subscriptions/fa5fc227-a624-475e-b696-cdd604c735bc/resourceGroups/<resource group>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/myId. Mutually exclusive with identityType systemAssignedIdentity.                                          |
 | federatedClientId?              | `Core.uuid`                                                                            | application client identity to use for accessing key encryption key Url in a different tenant. Ex: f83c6b1b-4d34-47e4-bb34-9d83df58b540                                                                                                                                                                                            |
-| delegatedIdentityClientId       | `Core.uuid`                                                                            | delegated identity to use for accessing key encryption key Url. Ex: /subscriptions/fa5fc227-a624-475e-b696-cdd604c735bc/resourceGroups/<resource group>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/myId. Mutually exclusive with identityType systemAssignedIdentity and userAssignedIdentity - internal use only. |
+| delegatedIdentityClientId?      | `Core.uuid`                                                                            | delegated identity to use for accessing key encryption key Url. Ex: /subscriptions/fa5fc227-a624-475e-b696-cdd604c735bc/resourceGroups/<resource group>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/myId. Mutually exclusive with identityType systemAssignedIdentity and userAssignedIdentity - internal use only. |
 
 ### `DefaultProvisioningStateProperty` {#Azure.ResourceManager.DefaultProvisioningStateProperty}
 
diff --git a/packages/typespec-azure-resource-manager/lib/customer-managed-keys.tsp b/packages/typespec-azure-resource-manager/lib/customer-managed-keys.tsp
index 86b7def299..c0b3306fdc 100644
--- a/packages/typespec-azure-resource-manager/lib/customer-managed-keys.tsp
+++ b/packages/typespec-azure-resource-manager/lib/customer-managed-keys.tsp
@@ -40,7 +40,7 @@ model CustomerManagedKeyEncryption {
   federatedClientId?: uuid;
 
   @doc("delegated identity to use for accessing key encryption key Url. Ex: /subscriptions/fa5fc227-a624-475e-b696-cdd604c735bc/resourceGroups/<resource group>/providers/Microsoft.ManagedIdentity/userAssignedIdentities/myId. Mutually exclusive with identityType systemAssignedIdentity and userAssignedIdentity - internal use only.")
-  delegatedIdentityClientId: uuid;
+  delegatedIdentityClientId?: uuid;
 }
 
 @doc("All encryption configuration for a resource.")