diff --git a/eth2/utils/bls/src/aggregate_public_key.rs b/eth2/utils/bls/src/aggregate_public_key.rs
index d36477d760..2980462486 100644
--- a/eth2/utils/bls/src/aggregate_public_key.rs
+++ b/eth2/utils/bls/src/aggregate_public_key.rs
@@ -1,5 +1,6 @@
 use super::PublicKey;
 use milagro_bls::AggregatePublicKey as RawAggregatePublicKey;
+use serde_hex::encode as hex_encode;
 
 /// A BLS aggregate public key.
 ///
@@ -21,4 +22,10 @@ impl AggregatePublicKey {
     pub fn as_raw(&self) -> &RawAggregatePublicKey {
         &self.0
     }
+
+    /// 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())
+    }
 }
diff --git a/eth2/utils/bls/src/aggregate_signature.rs b/eth2/utils/bls/src/aggregate_signature.rs
index cf7ce78c26..f434feb0d7 100644
--- a/eth2/utils/bls/src/aggregate_signature.rs
+++ b/eth2/utils/bls/src/aggregate_signature.rs
@@ -129,6 +129,12 @@ impl AggregateSignature {
             is_empty: true,
         }
     }
+
+    /// Return a hex string representation of the bytes of this signature.
+    #[cfg(test)]
+    pub fn as_hex_string(&self) -> String {
+        hex_encode(self.as_bytes())
+    }
 }
 
 impl_ssz!(