diff --git a/src/serde_helpers.rs b/src/serde_helpers.rs
index b015c3ea..e836d1c0 100644
--- a/src/serde_helpers.rs
+++ b/src/serde_helpers.rs
@@ -23,6 +23,11 @@ pub use hex_string_as_object_id::{
     serialize as serialize_hex_string_as_object_id,
 };
 #[doc(inline)]
+pub use i64_as_datetime::{
+    deserialize as deserialize_i64_from_datetime,
+    serialize as serialize_i64_as_datetime,
+};
+#[doc(inline)]
 pub use rfc3339_string_as_bson_datetime::{
     deserialize as deserialize_rfc3339_string_from_bson_datetime,
     serialize as serialize_rfc3339_string_as_bson_datetime,
@@ -412,6 +417,40 @@ pub mod hex_string_as_object_id {
     }
 }
 
+/// Contains functions to `serialize` a `i64` integer as `DateTime` and `deserialize`
+/// a `i64` integer from `DateTime`
+///
+/// ### The i64 should represent seconds `(DateTime::timestamp_millis(..))`.
+///
+/// ```rust
+/// # use serde::{Serialize, Deserialize};
+/// # use bson::serde_helpers::i64_as_datetime;
+/// #[derive(Serialize, Deserialize)]
+/// struct Item {
+///     #[serde(with = "i64_as_datetime")]
+///     pub now: i64,
+/// }
+/// ```
+pub mod i64_as_datetime {
+    use crate::DateTime;
+    use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+    /// Deserializes a i64 integer from a DateTime.
+    pub fn deserialize<'de, D>(deserializer: D) -> Result<i64, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let date: DateTime = DateTime::deserialize(deserializer)?;
+        Ok(date.timestamp_millis())
+    }
+
+    /// Serializes a i64 integer as a DateTime.
+    pub fn serialize<S: Serializer>(val: &i64, serializer: S) -> Result<S::Ok, S::Error> {
+        let date_time = DateTime::from_millis(*val);
+        date_time.serialize(serializer)
+    }
+}
+
 #[allow(unused_macros)]
 macro_rules! as_binary_mod {
     ($feat:meta, $uu:path) => {
diff --git a/src/tests/serde.rs b/src/tests/serde.rs
index 362587a8..0718c2e9 100644
--- a/src/tests/serde.rs
+++ b/src/tests/serde.rs
@@ -10,6 +10,7 @@ use crate::{
     serde_helpers::{
         bson_datetime_as_rfc3339_string,
         hex_string_as_object_id,
+        i64_as_datetime,
         rfc3339_string_as_bson_datetime,
         serialize_object_id_as_hex_string,
         timestamp_as_u32,
@@ -886,6 +887,26 @@ fn test_oid_helpers() {
     assert_eq!(a.oid, oid.to_string());
 }
 
+#[test]
+fn test_i64_as_datetime() {
+    let _guard = LOCK.run_concurrently();
+
+    #[derive(Serialize, Deserialize)]
+    struct A {
+        #[serde(with = "i64_as_datetime")]
+        now: i64,
+    }
+
+    let now = DateTime::now();
+    let a = A {
+        now: now.timestamp_millis(),
+    };
+    let doc = to_document(&a).unwrap();
+    assert_eq!(doc.get_datetime("now").unwrap(), &now);
+    let a: A = from_document(doc).unwrap();
+    assert_eq!(a.now, now.timestamp_millis());
+}
+
 #[test]
 #[cfg(feature = "uuid-0_8")]
 fn test_uuid_0_8_helpers() {