diff --git a/output/openapi/elasticsearch-openapi.json b/output/openapi/elasticsearch-openapi.json
index a416aedf9f..8b3580db79 100644
--- a/output/openapi/elasticsearch-openapi.json
+++ b/output/openapi/elasticsearch-openapi.json
@@ -95446,6 +95446,14 @@
               }
             ]
           },
+          "age_in_millis": {
+            "x-state": "Generally available; Added in 9.2.0",
+            "allOf": [
+              {
+                "$ref": "#/components/schemas/_types.DurationValueUnitMillis"
+              }
+            ]
+          },
           "failed_step": {
             "allOf": [
               {
diff --git a/output/schema/schema.json b/output/schema/schema.json
index 75a2b0e795..0c1103f390 100644
--- a/output/schema/schema.json
+++ b/output/schema/schema.json
@@ -144650,7 +144650,7 @@
         "name": "LifecycleExplain",
         "namespace": "ilm.explain_lifecycle"
       },
-      "specLocation": "ilm/explain_lifecycle/types.ts#L65-L68",
+      "specLocation": "ilm/explain_lifecycle/types.ts#L75-L78",
       "type": {
         "kind": "union_of",
         "items": [
@@ -144735,6 +144735,32 @@
             }
           }
         },
+        {
+          "availability": {
+            "stack": {
+              "since": "9.2.0",
+              "stability": "stable"
+            }
+          },
+          "name": "age_in_millis",
+          "required": false,
+          "type": {
+            "kind": "instance_of",
+            "generics": [
+              {
+                "kind": "instance_of",
+                "type": {
+                  "name": "UnitMillis",
+                  "namespace": "_types"
+                }
+              }
+            ],
+            "type": {
+              "name": "DurationValue",
+              "namespace": "_types"
+            }
+          }
+        },
         {
           "name": "failed_step",
           "required": false,
@@ -145047,7 +145073,7 @@
           }
         }
       ],
-      "specLocation": "ilm/explain_lifecycle/types.ts#L27-L58"
+      "specLocation": "ilm/explain_lifecycle/types.ts#L33-L68"
     },
     {
       "kind": "interface",
@@ -145110,7 +145136,7 @@
           }
         }
       ],
-      "specLocation": "ilm/explain_lifecycle/types.ts#L70-L75"
+      "specLocation": "ilm/explain_lifecycle/types.ts#L80-L85"
     },
     {
       "kind": "interface",
@@ -145139,7 +145165,7 @@
           }
         }
       ],
-      "specLocation": "ilm/explain_lifecycle/types.ts#L60-L63"
+      "specLocation": "ilm/explain_lifecycle/types.ts#L70-L73"
     },
     {
       "kind": "request",
diff --git a/output/typescript/types.ts b/output/typescript/types.ts
index 04b2414291..06a657694a 100644
--- a/output/typescript/types.ts
+++ b/output/typescript/types.ts
@@ -11551,6 +11551,7 @@ export interface IlmExplainLifecycleLifecycleExplainManaged {
   action_time?: DateTime
   action_time_millis?: EpochTime<UnitMillis>
   age?: Duration
+  age_in_millis?: DurationValue<UnitMillis>
   failed_step?: Name
   failed_step_retry_count?: integer
   index: IndexName
diff --git a/specification/ilm/explain_lifecycle/types.ts b/specification/ilm/explain_lifecycle/types.ts
index 93765ca723..41a00271fb 100644
--- a/specification/ilm/explain_lifecycle/types.ts
+++ b/specification/ilm/explain_lifecycle/types.ts
@@ -19,7 +19,13 @@
 
 import { IndexName, Name, VersionNumber } from '@_types/common'
 import { integer } from '@_types/Numeric'
-import { DateTime, Duration, EpochTime, UnitMillis } from '@_types/Time'
+import {
+  DateTime,
+  Duration,
+  DurationValue,
+  EpochTime,
+  UnitMillis
+} from '@_types/Time'
 import { Phase } from '@ilm/_types/Phase'
 import { Dictionary } from '@spec_utils/Dictionary'
 import { UserDefinedValue } from '@spec_utils/UserDefinedValue'
@@ -30,6 +36,10 @@ export class LifecycleExplainManaged {
   action_time_millis?: EpochTime<UnitMillis>
   /* `lifecycle_date` as a duration */
   age?: Duration
+  /**
+   * @availability stack since=9.2.0 stability=stable
+   */
+  age_in_millis?: DurationValue<UnitMillis>
   failed_step?: Name
   failed_step_retry_count?: integer
   index: IndexName