diff --git a/jsonata.d.ts b/jsonata.d.ts
index 1b21a454..e71583a4 100644
--- a/jsonata.d.ts
+++ b/jsonata.d.ts
@@ -37,7 +37,7 @@ declare namespace jsonata {
     readonly input: any;
   }
   interface Expression {
-    evaluate(input: any, bindings?: Record<string, any>): any;
+    evaluate(input: any, bindings?: Record<string, any>): Promise<any>;
     evaluate(input: any, bindings: Record<string, any> | undefined, callback: (err: JsonataError, resp: any) => void): void;
     assign(name: string, value: any): void;
     registerFunction(name: string, implementation: (this: Focus, ...args: any[]) => any, signature?: string): void;