diff --git a/beacon_node/src/main.rs b/beacon_node/src/main.rs
index 072315b6b..eb0b38d5f 100644
--- a/beacon_node/src/main.rs
+++ b/beacon_node/src/main.rs
@@ -108,7 +108,7 @@ fn main() {
                 deposit_input: DepositInput {
                     pubkey: keypair.pk.clone(),
                     withdrawal_credentials: Hash256::zero(), // Withdrawal not possible.
-                    proof_of_possession: create_proof_of_possession(&keypair),
+                    proof_of_possession: create_proof_of_possession(&keypair, Hash256::zero()),
                 },
             },
         })
diff --git a/eth2/utils/bls/src/lib.rs b/eth2/utils/bls/src/lib.rs
index 8b3f8b2ba..95f993ecb 100644
--- a/eth2/utils/bls/src/lib.rs
+++ b/eth2/utils/bls/src/lib.rs
@@ -20,6 +20,7 @@ pub const BLS_AGG_SIG_BYTE_SIZE: usize = 96;
 
 use hashing::hash;
 use ssz::ssz_encode;
+use types::{DepositInput, Hash256};
 
 /// For some signature and public key, ensure that the signature message was the public key and it
 /// was signed by the secret key that corresponds to that public key.
@@ -31,7 +32,7 @@ pub fn verify_proof_of_possession(sig: &Signature, pubkey: &PublicKey) -> bool {
 
 // TODO: Update this method
 // https://github.com/sigp/lighthouse/issues/239
-pub fn create_proof_of_possession(keypair: &Keypair) -> Signature {
+pub fn create_proof_of_possession(keypair: &Keypair, withdrawal_credentials: &Hash256) -> Signature {
     Signature::new(&ssz_encode(&keypair.pk), 0, &keypair.sk)
 }