diff --git a/README.md b/README.md
index fef8994c..5fc419c6 100644
--- a/README.md
+++ b/README.md
@@ -215,6 +215,7 @@ for hero in create_superhero_team("The Food Dudes"):
 ### Additional Features
 
 - The `@prompt` decorator can also be used with `async` function definitions, which enables making concurrent queries to the LLM.
+- The `functions` argument to `@prompt` can contain async/coroutine functions. When the corresponding `FunctionCall` objects are called the result must be awaited.
 - The `Annotated` type annotation can be used to provide descriptions and other metadata for function parameters. See [the pydantic documentation on using `Field` to describe function arguments](https://docs.pydantic.dev/latest/usage/validation_decorator/#using-field-to-describe-function-arguments).
 - The `@prompt` and `@prompt_chain` decorators also accept a `model` argument. You can pass an instance of `OpenaiChatModel` (from `magentic.chat_model.openai_chat_model`) to use GPT4 or configure a different temperature.
 
diff --git a/tests/test_function_call.py b/tests/test_function_call.py
index 0d170d10..0bddc4b0 100644
--- a/tests/test_function_call.py
+++ b/tests/test_function_call.py
@@ -1,3 +1,5 @@
+import inspect
+
 import pytest
 
 from magentic.function_call import FunctionCall
@@ -47,3 +49,14 @@ def test_function_call_eq(left, right, equal):
 )
 def test_function_call_arguments(function_call, arguments):
     assert function_call.arguments == arguments
+
+
+@pytest.mark.asyncio
+async def test_function_call_async_function():
+    async def async_plus(a: int, b: int) -> int:
+        return a + b
+
+    function_call = FunctionCall(async_plus, a=1, b=2)
+    result = function_call()
+    assert inspect.isawaitable(result)
+    assert await result == 3
diff --git a/tests/test_prompt_function.py b/tests/test_prompt_function.py
index 7b8a70e4..83b28498 100644
--- a/tests/test_prompt_function.py
+++ b/tests/test_prompt_function.py
@@ -1,6 +1,7 @@
 """Tests for PromptFunction."""
 
 from inspect import getdoc
+from typing import Awaitable
 
 import pytest
 from pydantic import BaseModel
@@ -154,3 +155,23 @@ async def sum_populations(country_one: str, country_two: str) -> FunctionCall[in
     assert isinstance(output, FunctionCall)
     func_result = output()
     assert isinstance(func_result, int)
+
+
+@pytest.mark.asyncio
+@pytest.mark.openai
+async def test_async_decorator_return_async_function_call():
+    async def async_plus(a: int, b: int) -> int:
+        return a + b
+
+    @prompt(
+        "Sum the populations of {country_one} and {country_two}.",
+        functions=[async_plus],
+    )
+    async def sum_populations(
+        country_one: str, country_two: str
+    ) -> FunctionCall[Awaitable[int]]:
+        ...
+
+    output = await sum_populations("Ireland", "UK")
+    assert isinstance(output, FunctionCall)
+    assert isinstance(await output(), int)