diff --git a/bitcoin/tx.c b/bitcoin/tx.c
index b2f558413..ca0a15973 100644
--- a/bitcoin/tx.c
+++ b/bitcoin/tx.c
@@ -494,11 +494,6 @@ void bitcoin_tx_finalize(struct bitcoin_tx *tx)
 	assert(bitcoin_tx_check(tx));
 }
 
-char *bitcoin_tx_to_psbt_base64(const tal_t *ctx, struct bitcoin_tx *tx)
-{
-	return psbt_to_b64(ctx, tx->psbt);
-}
-
 struct bitcoin_tx *bitcoin_tx_with_psbt(const tal_t *ctx, struct wally_psbt *psbt STEALS)
 {
 	struct bitcoin_tx *tx = bitcoin_tx(ctx, chainparams,
diff --git a/bitcoin/tx.h b/bitcoin/tx.h
index 4c7209081..982f6ff22 100644
--- a/bitcoin/tx.h
+++ b/bitcoin/tx.h
@@ -220,10 +220,5 @@ void towire_bitcoin_txid(u8 **pptr, const struct bitcoin_txid *txid);
 void towire_bitcoin_tx(u8 **pptr, const struct bitcoin_tx *tx);
 void towire_bitcoin_tx_output(u8 **pptr, const struct bitcoin_tx_output *output);
 
-/*
- * Get the base64 string encoded PSBT of a bitcoin transaction.
- */
-char *bitcoin_tx_to_psbt_base64(const tal_t *ctx, struct bitcoin_tx *tx);
-
 int wally_tx_clone(struct wally_tx *tx, struct wally_tx **output);
 #endif /* LIGHTNING_BITCOIN_TX_H */
diff --git a/common/json_helpers.c b/common/json_helpers.c
index 42841b90e..f82e4b8a0 100644
--- a/common/json_helpers.c
+++ b/common/json_helpers.c
@@ -1,6 +1,7 @@
 #include <arpa/inet.h>
 #include <bitcoin/preimage.h>
 #include <bitcoin/privkey.h>
+#include <bitcoin/psbt.h>
 #include <bitcoin/pubkey.h>
 #include <bitcoin/short_channel_id.h>
 #include <ccan/ccan/str/hex/hex.h>
@@ -242,10 +243,10 @@ void json_add_tx(struct json_stream *result,
 
 void json_add_psbt(struct json_stream *stream,
 		   const char *fieldname,
-		   struct bitcoin_tx *tx)
+		   struct wally_psbt *psbt)
 {
 	const char *psbt_b64;
-	psbt_b64 = bitcoin_tx_to_psbt_base64(tx, tx);
+	psbt_b64 = psbt_to_b64(NULL, psbt);
 	json_add_string(stream, fieldname, take(psbt_b64));
 }
 
diff --git a/common/json_helpers.h b/common/json_helpers.h
index 230f1a5ba..248344f20 100644
--- a/common/json_helpers.h
+++ b/common/json_helpers.h
@@ -141,6 +141,6 @@ void json_add_tx(struct json_stream *result,
 /* '"fieldname" : "cHNidP8BAJoCAAAAAljo..." or "cHNidP8BAJoCAAAAAljo..." if fieldname is NULL */
 void json_add_psbt(struct json_stream *stream,
 		   const char *fieldname,
-		   struct bitcoin_tx *tx);
+		   struct wally_psbt *psbt);
 
 #endif /* LIGHTNING_COMMON_JSON_HELPERS_H */
diff --git a/wallet/walletrpc.c b/wallet/walletrpc.c
index 068c3d44b..9d7e4dcbb 100644
--- a/wallet/walletrpc.c
+++ b/wallet/walletrpc.c
@@ -442,7 +442,7 @@ static struct command_result *json_txprepare(struct command *cmd,
 	response = json_stream_success(cmd);
 	json_add_tx(response, "unsigned_tx", utx->tx);
 	json_add_txid(response, "txid", &utx->txid);
-	json_add_psbt(response, "psbt", utx->tx);
+	json_add_psbt(response, "psbt", utx->tx->psbt);
 	return command_success(cmd, response);
 }
 static const struct json_command txprepare_command = {