diff --git a/crates/ruma-serde/src/strings.rs b/crates/ruma-serde/src/strings.rs
index 9482ebfe..4183f731 100644
--- a/crates/ruma-serde/src/strings.rs
+++ b/crates/ruma-serde/src/strings.rs
@@ -15,7 +15,7 @@ use serde::{
 /// formulation in the spec.
 ///
 /// To be used like this:
-/// `#[serde(deserialize_with = "empty_string_as_none")]`
+/// `#[serde(default, deserialize_with = "empty_string_as_none")]`
 /// Relevant serde issue: <https://github.com/serde-rs/serde/issues/1425>
 pub fn empty_string_as_none<'de, D, T>(de: D) -> Result<Option<T>, D::Error>
 where