diff --git a/examples/function_call.rs b/examples/function_call.rs
index a656de3..1961778 100644
--- a/examples/function_call.rs
+++ b/examples/function_call.rs
@@ -1,5 +1,5 @@
 use openai_api_rs::v1::api::Client;
-use openai_api_rs::v1::chat_completion::{self, ChatCompletionRequest};
+use openai_api_rs::v1::chat_completion::{self, ChatCompletionRequest, FunctionCallType};
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use std::{env, vec};
@@ -46,7 +46,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
                 required: Some(vec![String::from("coin")]),
             },
         }]),
-        function_call: Some("auto".to_string()),
+        function_call: Some(FunctionCallType::auto), //Some(FunctionCallType::Function { name: "test".to_string() })
         temperature: None,
         top_p: None,
         n: None,
diff --git a/src/v1/chat_completion.rs b/src/v1/chat_completion.rs
index 6de6381..5354bd1 100644
--- a/src/v1/chat_completion.rs
+++ b/src/v1/chat_completion.rs
@@ -13,6 +13,13 @@ pub const GPT4_32K: &str = "gpt-4-32k";
 pub const GPT4_32K_0314: &str = "gpt-4-32k-0314";
 pub const GPT4_0613: &str = "gpt-4-0613";
 
+#[derive(Debug, Serialize)]
+#[allow(non_camel_case_types)]
+pub enum FunctionCallType {
+    auto,
+    function { name: String },
+}
+
 #[derive(Debug, Serialize)]
 pub struct ChatCompletionRequest {
     pub model: String,
@@ -20,7 +27,7 @@ pub struct ChatCompletionRequest {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub functions: Option<Vec<Function>>,
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub function_call: Option<String>,
+    pub function_call: Option<FunctionCallType>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub temperature: Option<f64>,
     #[serde(skip_serializing_if = "Option::is_none")]