diff --git a/packages/svelte/src/attachments/index.js b/packages/svelte/src/attachments/index.js
index 785a4e096a..514c9433f4 100644
--- a/packages/svelte/src/attachments/index.js
+++ b/packages/svelte/src/attachments/index.js
@@ -31,6 +31,20 @@ export function createAttachmentKey() {
 	return Symbol(ATTACHMENT_KEY);
 }
 
+/**
+ * @template {EventTarget} E
+ * @template {unknown} T
+ * @overload
+ * @param {Action<E, T> | function(E, T): void | ActionReturn<T>} action The action function
+ * @param {() => T} fn A function that returns the argument for the action
+ * @returns {Attachment<E>}
+ */
+/**
+ * @template {EventTarget} E
+ * @overload
+ * @param {Action<E, void> | function(E): void | ActionReturn<void>} action The action function
+ * @returns {Attachment<E>}
+ */
 /**
  * Converts an Action into an Attachment keeping the same behavior. It's useful if you want to start using
  * attachments on Components but you have library provided actions.
@@ -41,7 +55,7 @@ export function createAttachmentKey() {
  * @template {EventTarget} E
  * @template {unknown} T
  * @param {Action<E, T> | function(E, T): void | ActionReturn<T>} action The action function
- * @param {() => T} [fn] A function that returns the argument for the action
+ * @param {() => T} fn A function that returns the argument for the action
  * @returns {Attachment<E>}
  * @since 5.32
  */
diff --git a/packages/svelte/types/index.d.ts b/packages/svelte/types/index.d.ts
index 14a04f1f3a..067e04db5b 100644
--- a/packages/svelte/types/index.d.ts
+++ b/packages/svelte/types/index.d.ts
@@ -659,18 +659,10 @@ declare module 'svelte/attachments' {
 	 * @since 5.29
 	 */
 	export function createAttachmentKey(): symbol;
-	/**
-	 * Converts an Action into an Attachment keeping the same behavior. It's useful if you want to start using
-	 * attachments on Components but you have library provided actions.
-	 *
-	 * Note that the second argument, if provided, must be a function that _returns_ the argument to the
-	 * action function, not the argument itself.
-	 *
-	 * @param action The action function
-	 * @param fn A function that returns the argument for the action
-	 * @since 5.32
-	 */
-	export function fromAction<E extends EventTarget, T extends unknown>(action: Action<E, T> | ((arg0: E, arg1: T) => void | ActionReturn<T>), fn?: (() => T) | undefined): Attachment<E>;
+
+	export function fromAction<E extends EventTarget, T extends unknown>(action: Action<E, T> | ((arg0: E, arg1: T) => void | ActionReturn<T>), fn: () => T): Attachment<E>;
+
+	export function fromAction<E extends EventTarget>(action: Action<E, void> | ((arg0: E) => void | ActionReturn<void>)): Attachment<E>;
 
 	export {};
 }