diff --git a/eth2/utils/bls/src/aggregate_public_key.rs b/eth2/utils/bls/src/aggregate_public_key.rs
index 298046248..38637cec7 100644
--- a/eth2/utils/bls/src/aggregate_public_key.rs
+++ b/eth2/utils/bls/src/aggregate_public_key.rs
@@ -1,6 +1,5 @@
 use super::PublicKey;
 use milagro_bls::AggregatePublicKey as RawAggregatePublicKey;
-use serde_hex::encode as hex_encode;
 
 /// A BLS aggregate public key.
 ///
@@ -26,6 +25,6 @@ impl AggregatePublicKey {
     /// Return a hex string representation of this key's bytes.
     #[cfg(test)]
     pub fn as_hex_string(&self) -> String {
-        hex_encode(self.as_raw().as_bytes())
+        serde_hex::encode(self.as_raw().as_bytes())
     }
 }