diff --git a/specification/synapse/data-plane/Microsoft.Synapse/preview/2021-06-01-preview/entityTypes/LinkedService.json b/specification/synapse/data-plane/Microsoft.Synapse/preview/2021-06-01-preview/entityTypes/LinkedService.json
index b43615929a7c..f85730971b13 100644
--- a/specification/synapse/data-plane/Microsoft.Synapse/preview/2021-06-01-preview/entityTypes/LinkedService.json
+++ b/specification/synapse/data-plane/Microsoft.Synapse/preview/2021-06-01-preview/entityTypes/LinkedService.json
@@ -764,7 +764,7 @@
         "ServicePrincipalKey",
         "ServicePrincipalCert"
       ],
-      "type": "object",
+      "type": "string",
       "description": "The service principal credential type to use in Server-To-Server authentication. 'ServicePrincipalKey' for key/secret, 'ServicePrincipalCert' for certificate. Type: string (or Expression with resultType string)."
     },
     "CommonDataServiceForAppsLinkedService": {
diff --git a/specification/synapse/data-plane/Microsoft.Synapse/stable/2020-12-01/entityTypes/LinkedService.json b/specification/synapse/data-plane/Microsoft.Synapse/stable/2020-12-01/entityTypes/LinkedService.json
index a9f218b38f20..c9d58336b25b 100644
--- a/specification/synapse/data-plane/Microsoft.Synapse/stable/2020-12-01/entityTypes/LinkedService.json
+++ b/specification/synapse/data-plane/Microsoft.Synapse/stable/2020-12-01/entityTypes/LinkedService.json
@@ -764,7 +764,7 @@
         "ServicePrincipalKey",
         "ServicePrincipalCert"
       ],
-      "type": "object",
+      "type": "string",
       "description": "The service principal credential type to use in Server-To-Server authentication. 'ServicePrincipalKey' for key/secret, 'ServicePrincipalCert' for certificate. Type: string (or Expression with resultType string)."
     },
     "CommonDataServiceForAppsLinkedService": {