diff --git a/packages/forms/src/directives/ng_model.ts b/packages/forms/src/directives/ng_model.ts
index b4e252a9cb..1a91885f27 100644
--- a/packages/forms/src/directives/ng_model.ts
+++ b/packages/forms/src/directives/ng_model.ts
@@ -136,6 +136,16 @@ const resolvedPromise = (() => Promise.resolve(null))();
 export class NgModel extends NgControl implements OnChanges,
     OnDestroy {
   public readonly control: FormControl = new FormControl();
+
+  // At runtime we coerce arbitrary values assigned to the "disabled" input to a "boolean".
+  // This is not reflected in the type of the property because outside of templates, consumers
+  // should only deal with booleans. In templates, a string is allowed for convenience and to
+  // match the native "disabled attribute" semantics which can be observed on input elements.
+  // This static member tells the compiler that values of type "string" can also be assigned
+  // to the input in a template.
+  /** @nodoc */
+  static ngAcceptInputType_disabled: boolean|string;
+
   /** @internal */
   _registered = false;
 
diff --git a/tools/public_api_guard/forms/forms.d.ts b/tools/public_api_guard/forms/forms.d.ts
index 756a1654d4..4780d5b0f7 100644
--- a/tools/public_api_guard/forms/forms.d.ts
+++ b/tools/public_api_guard/forms/forms.d.ts
@@ -415,6 +415,7 @@ export declare class NgModel extends NgControl implements OnChanges, OnDestroy {
     ngOnChanges(changes: SimpleChanges): void;
     ngOnDestroy(): void;
     viewToModelUpdate(newValue: any): void;
+    static ngAcceptInputType_disabled: boolean | string;
 }
 
 export declare class NgModelGroup extends AbstractFormGroupDirective implements OnInit, OnDestroy {