diff --git a/Cargo.toml b/Cargo.toml
index 4d28f1e..f60be9c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,6 +14,7 @@ derive_more = "0.99.17"
 lazy_static = "1.4.0"
 regex = "1.7.1"
 serde = { version = "1.0.152", features = ["derive"], default-features = false }
+thiserror = "1.0.50"
 
 [dev-dependencies]
 serde_test = "1.0.152"
diff --git a/src/lib.rs b/src/lib.rs
index 8a4ec17..848f62f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -68,6 +68,7 @@ use regex::Regex;
 use serde::de::Visitor;
 use serde::Deserialize;
 use serde::Serialize;
+use thiserror::Error;
 
 /// A point in time.
 ///
@@ -339,7 +340,7 @@ impl Debug for Time {
         write!(f, "{:02}:", minutes_part)?;
         write!(f, "{:02}", seconds_part)?;
         if millis_part > 0 {
-            write!(f, ".{}", millis_part)?;
+            write!(f, ".{:03}", millis_part)?;
         }
         Ok(())
     }
@@ -1434,6 +1435,11 @@ mod time_test {
                 input: Time::millis(i64::MIN),
                 expected: "-2562047788015:12:55.808".to_string(),
             },
+            TestCase {
+                name: "millis",
+                input: Time::hours(3) + Duration::millis(42),
+                expected: "03:00:00.042".to_string(),
+            },
         ];
         for test in tests {
             assert_eq!(