diff --git a/release-notes.md b/release-notes.md
index 49769dee..98281b4a 100644
--- a/release-notes.md
+++ b/release-notes.md
@@ -1,5 +1,9 @@
 # Release Notes
 
+## 8.0.1
+
+- [#610](https://github.com/kpdecker/jsdiff/pull/610) **Fixes types for `diffJson` which were broken by 8.0.0**. The new bundled types in 8.0.0 only allowed `diffJson` to be passed string arguments, but it should've been possible to pass either strings or objects (and now is). Thanks to Josh Kelley for the fix.
+
 ## 8.0.0
 
 - [#580](https://github.com/kpdecker/jsdiff/pull/580) **Multiple tweaks to `diffSentences`**:
diff --git a/src/diff/base.ts b/src/diff/base.ts
index cfc3719d..ef2dd462 100644
--- a/src/diff/base.ts
+++ b/src/diff/base.ts
@@ -23,36 +23,37 @@ interface Path {
 
 export default class Diff<
   TokenT,
-  ValueT extends Iterable<TokenT> = Iterable<TokenT>
+  ValueT extends Iterable<TokenT> = Iterable<TokenT>,
+  InputValueT = ValueT
 > {
   diff(
-    oldStr: ValueT,
-    newStr: ValueT,
+    oldStr: InputValueT,
+    newStr: InputValueT,
     options: DiffCallbackNonabortable<ValueT>
   ): undefined;
   diff(
-    oldStr: ValueT,
-    newStr: ValueT,
+    oldStr: InputValueT,
+    newStr: InputValueT,
     options: AllDiffOptions & AbortableDiffOptions & CallbackOptionAbortable<ValueT>
   ): undefined
   diff(
-    oldStr: ValueT,
-    newStr: ValueT,
+    oldStr: InputValueT,
+    newStr: InputValueT,
     options: AllDiffOptions & CallbackOptionNonabortable<ValueT>
   ): undefined
   diff(
-    oldStr: ValueT,
-    newStr: ValueT,
+    oldStr: InputValueT,
+    newStr: InputValueT,
     options: AllDiffOptions & AbortableDiffOptions
   ): ChangeObject<ValueT>[] | undefined
   diff(
-    oldStr: ValueT,
-    newStr: ValueT,
+    oldStr: InputValueT,
+    newStr: InputValueT,
     options?: AllDiffOptions
   ): ChangeObject<ValueT>[]
   diff(
-    oldString: ValueT,
-    newString: ValueT,
+    oldStr: InputValueT,
+    newStr: InputValueT,
     // Type below is not accurate/complete - see above for full possibilities - but it compiles
     options: DiffCallbackNonabortable<ValueT> | AllDiffOptions & Partial<CallbackOptionNonabortable<ValueT>> = {}
   ): ChangeObject<ValueT>[] | undefined {
@@ -64,8 +65,8 @@ export default class Diff<
       callback = options.callback;
     }
     // Allow subclasses to massage the input prior to running
-    oldString = this.castInput(oldString, options);
-    newString = this.castInput(newString, options);
+    const oldString = this.castInput(oldStr, options);
+    const newString = this.castInput(newStr, options);
 
     const oldTokens = this.removeEmpty(this.tokenize(oldString, options));
     const newTokens = this.removeEmpty(this.tokenize(newString, options));
@@ -282,8 +283,8 @@ export default class Diff<
   }
 
   // eslint-disable-next-line @typescript-eslint/no-unused-vars
-  castInput(value: ValueT, options: AllDiffOptions): ValueT {
-    return value;
+  castInput(value: InputValueT, options: AllDiffOptions): ValueT {
+    return value as unknown as ValueT;
   }
 
   // eslint-disable-next-line @typescript-eslint/no-unused-vars
diff --git a/src/diff/json.ts b/src/diff/json.ts
index be7e7c4c..898cd3f4 100644
--- a/src/diff/json.ts
+++ b/src/diff/json.ts
@@ -2,7 +2,7 @@ import Diff from './base.js';
 import type { ChangeObject, CallbackOptionAbortable, CallbackOptionNonabortable, DiffCallbackNonabortable, DiffJsonOptionsAbortable, DiffJsonOptionsNonabortable} from '../types.js';
 import { tokenize } from './line.js';
 
-class JsonDiff extends Diff<string, string> {
+class JsonDiff extends Diff<string, string, string | object> {
   get useLongestToken() {
     // Discriminate between two lines of pretty-printed, serialized JSON where one of them has a
     // dangling comma and the other doesn't. Turns out including the dangling comma yields the nicest output:
@@ -11,7 +11,7 @@ class JsonDiff extends Diff<string, string> {
 
   tokenize = tokenize;
 
-  castInput(value: string, options: DiffJsonOptionsNonabortable | DiffJsonOptionsAbortable) {
+  castInput(value: string | object, options: DiffJsonOptionsNonabortable | DiffJsonOptionsAbortable) {
     const {undefinedReplacement, stringifyReplacer = (k, v) => typeof v === 'undefined' ? undefinedReplacement : v} = options;
 
     return typeof value === 'string' ? value : JSON.stringify(canonicalize(value, null, null, stringifyReplacer), null, '  ');
@@ -31,31 +31,31 @@ export const jsonDiff = new JsonDiff();
  * @returns a list of change objects.
  */
 export function diffJson(
-  oldStr: string,
-  newStr: string,
+  oldStr: string | object,
+  newStr: string | object,
   options: DiffCallbackNonabortable<string>
 ): undefined;
 export function diffJson(
-  oldStr: string,
-  newStr: string,
+  oldStr: string | object,
+  newStr: string | object,
   options: DiffJsonOptionsAbortable & CallbackOptionAbortable<string>
 ): undefined
 export function diffJson(
-  oldStr: string,
-  newStr: string,
+  oldStr: string | object,
+  newStr: string | object,
   options: DiffJsonOptionsNonabortable & CallbackOptionNonabortable<string>
 ): undefined
 export function diffJson(
-  oldStr: string,
-  newStr: string,
+  oldStr: string | object,
+  newStr: string | object,
   options: DiffJsonOptionsAbortable
 ): ChangeObject<string>[] | undefined
 export function diffJson(
-  oldStr: string,
-  newStr: string,
+  oldStr: string | object,
+  newStr: string | object,
   options?: DiffJsonOptionsNonabortable
 ): ChangeObject<string>[]
-export function diffJson(oldStr: string, newStr: string, options?: any): undefined | ChangeObject<string>[] {
+export function diffJson(oldStr: string | object, newStr: string | object, options?: any): undefined | ChangeObject<string>[] {
   return jsonDiff.diff(oldStr, newStr, options);
 }