diff --git a/src/psbt.js b/src/psbt.js
index ec91bd9..b9ed061 100644
--- a/src/psbt.js
+++ b/src/psbt.js
@@ -175,20 +175,23 @@ class Psbt extends bip174_1.Psbt {
     return this.addPartialSigToInput(inputIndex, partialSig);
   }
   signInputAsync(inputIndex, keyPair) {
-    if (!keyPair || !keyPair.publicKey)
-      throw new Error('Need Signer to sign input');
-    const { hash, sighashType } = getHashAndSighashType(
-      this.inputs,
-      inputIndex,
-      keyPair.publicKey,
-      this.globalMap.unsignedTx,
-    );
-    return keyPair.sign(hash).then(signature => {
-      const partialSig = {
-        pubkey: keyPair.publicKey,
-        signature: bscript.signature.encode(signature, sighashType),
-      };
-      this.addPartialSigToInput(inputIndex, partialSig);
+    return new Promise((resolve, reject) => {
+      if (!keyPair || !keyPair.publicKey)
+        return reject(new Error('Need Signer to sign input'));
+      const { hash, sighashType } = getHashAndSighashType(
+        this.inputs,
+        inputIndex,
+        keyPair.publicKey,
+        this.globalMap.unsignedTx,
+      );
+      Promise.resolve(keyPair.sign(hash)).then(signature => {
+        const partialSig = {
+          pubkey: keyPair.publicKey,
+          signature: bscript.signature.encode(signature, sighashType),
+        };
+        this.addPartialSigToInput(inputIndex, partialSig);
+        resolve();
+      });
     });
   }
 }
diff --git a/ts_src/psbt.ts b/ts_src/psbt.ts
index 46e9487..2c36130 100644
--- a/ts_src/psbt.ts
+++ b/ts_src/psbt.ts
@@ -214,23 +214,28 @@ export class Psbt extends PsbtBase {
   }
 
   signInputAsync(inputIndex: number, keyPair: SignerAsync): Promise<void> {
-    if (!keyPair || !keyPair.publicKey)
-      throw new Error('Need Signer to sign input');
-    const { hash, sighashType } = getHashAndSighashType(
-      this.inputs,
-      inputIndex,
-      keyPair.publicKey,
-      this.globalMap.unsignedTx!,
-    );
+    return new Promise(
+      (resolve, reject): void => {
+        if (!keyPair || !keyPair.publicKey)
+          return reject(new Error('Need Signer to sign input'));
+        const { hash, sighashType } = getHashAndSighashType(
+          this.inputs,
+          inputIndex,
+          keyPair.publicKey,
+          this.globalMap.unsignedTx!,
+        );
 
-    return keyPair.sign(hash).then(signature => {
-      const partialSig = {
-        pubkey: keyPair.publicKey,
-        signature: bscript.signature.encode(signature, sighashType),
-      };
+        Promise.resolve(keyPair.sign(hash)).then(signature => {
+          const partialSig = {
+            pubkey: keyPair.publicKey,
+            signature: bscript.signature.encode(signature, sighashType),
+          };
 
-      this.addPartialSigToInput(inputIndex, partialSig);
-    });
+          this.addPartialSigToInput(inputIndex, partialSig);
+          resolve();
+        });
+      },
+    );
   }
 }