diff --git a/big-integer/big-integer.d.ts b/big-integer/big-integer.d.ts
index 633432e19..9e9127e83 100644
--- a/big-integer/big-integer.d.ts
+++ b/big-integer/big-integer.d.ts
@@ -214,7 +214,7 @@ interface BigIntegerStatic {
     /** Parse a Javascript number into a bigInt */
     ( number: number ): BigInteger;
     /** Parse a string into a bigInt */
-    ( string: string ): BigInteger;
+    ( string: string,  base?: string | number | BigInteger): BigInteger;
     /** no-op */
     ( bigInt: BigInteger ): BigInteger;
 }
@@ -223,4 +223,4 @@ declare var bigInt: BigIntegerStatic;
 
 declare module "big-integer" {
     export = bigInt;
-}
\ No newline at end of file
+}