diff --git a/packages/x-date-pickers/src/models/adapters.ts b/packages/x-date-pickers/src/models/adapters.ts
index 68891ae41b0b2..17c58ab20d994 100644
--- a/packages/x-date-pickers/src/models/adapters.ts
+++ b/packages/x-date-pickers/src/models/adapters.ts
@@ -155,7 +155,7 @@ export type AdapterOptions<TLocale, TInstance> = {
   locale?: TLocale;
 } & PropertyIfNotNever<'instance', TInstance>;
 
-export type DateBuilderReturnType<T extends string | null | undefined, TDate> = T extends null
+export type DateBuilderReturnType<T extends string | null | undefined, TDate> = [T] extends [null]
   ? null
   : TDate;
 
diff --git a/test/utils/pickers/describeGregorianAdapter/testCalculations.ts b/test/utils/pickers/describeGregorianAdapter/testCalculations.ts
index a8439902d70c0..90b8f60581e99 100644
--- a/test/utils/pickers/describeGregorianAdapter/testCalculations.ts
+++ b/test/utils/pickers/describeGregorianAdapter/testCalculations.ts
@@ -118,6 +118,12 @@ export const testCalculations: DescribeGregorianAdapterTestSuite = ({
         ).to.be.lessThan(5);
       }
     });
+
+    it('should work without args', () => {
+      const date = adapter.date().valueOf();
+
+      expect(Math.abs(date - Date.now())).to.be.lessThan(5);
+    });
   });
 
   it('Method: getTimezone', () => {