diff --git a/Sources/TextToSpeechV1/TextToSpeech.swift b/Sources/TextToSpeechV1/TextToSpeech.swift
index e64858267..bd5d35274 100644
--- a/Sources/TextToSpeechV1/TextToSpeech.swift
+++ b/Sources/TextToSpeechV1/TextToSpeech.swift
@@ -1342,7 +1342,6 @@ public class TextToSpeech {
        * The prompt audio must be in WAV format and must have a minimum sampling rate of 16 kHz. The service accepts
        audio with higher sampling rates. The service transcodes all audio to 16 kHz before processing it.
        * The length of the prompt audio is limited to 30 seconds.
-     - parameter filename: The filename for file.
      - parameter headers: A dictionary of request headers to be sent with this request.
      - parameter completionHandler: A function executed when the request completes with a successful result or error
      */
@@ -1351,7 +1350,6 @@ public class TextToSpeech {
         promptID: String,
         metadata: PromptMetadata,
         file: Data,
-        filename: String,
         headers: [String: String]? = nil,
         completionHandler: @escaping (WatsonResponse<Prompt>?, WatsonError?) -> Void)
     {
@@ -1363,7 +1361,7 @@ public class TextToSpeech {
         }
         multipartFormData.append(metadataJSON, withName: "metadata", mimeType: "application/json")
 
-        multipartFormData.append(file, withName: "file", mimeType: "audio/wav", fileName: filename)
+        multipartFormData.append(file, withName: "file", mimeType: "audio/wav", fileName: "filename")
         guard let body = try? multipartFormData.toData() else {
             completionHandler(nil, RestError.serialization(values: "request multipart form data"))
             return
diff --git a/Tests/TextToSpeechV1Tests/TextToSpeechTests.swift b/Tests/TextToSpeechV1Tests/TextToSpeechTests.swift
index 7b9e41b0e..a3a06418c 100644
--- a/Tests/TextToSpeechV1Tests/TextToSpeechTests.swift
+++ b/Tests/TextToSpeechV1Tests/TextToSpeechTests.swift
@@ -678,8 +678,7 @@ class TextToSpeechTests: XCTestCase {
         let promptMetadata = PromptMetadata(promptText: "Hello, how are you today?")
         let file = Bundle(for: type(of: self)).url(forResource: "custom_prompt_audio", withExtension: "wav")!
         let fileData = try! Data(contentsOf: file)
-        let filename = "custom_prompt_audio.wav"
-        textToSpeech.addCustomPrompt(customizationID: customizationID, promptID: promptID, metadata: promptMetadata, file: fileData, filename: filename) {
+        textToSpeech.addCustomPrompt(customizationID: customizationID, promptID: promptID, metadata: promptMetadata, file: fileData) {
             response, error in
             if let error = error {
                 if !error.localizedDescription.contains(self.litePlanMessage) {