diff --git a/coincurve/keys.py b/coincurve/keys.py
index 3823058..0ce29f4 100644
--- a/coincurve/keys.py
+++ b/coincurve/keys.py
@@ -470,7 +470,7 @@ class PublicKey:
         new_key = ffi.new('secp256k1_pubkey *')
 
         combined = lib.secp256k1_ec_pubkey_combine(
-            self.context.ctx, new_key, [pk.public_key for pk in public_keys], len(public_keys)
+            self.context.ctx, new_key, [pk.public_key for pk in [self, *public_keys]], len(public_keys) + 1
         )
 
         if not combined:
diff --git a/tests/test_keys.py b/tests/test_keys.py
index e2a2b76..89190c2 100644
--- a/tests/test_keys.py
+++ b/tests/test_keys.py
@@ -140,3 +140,9 @@ class TestPublicKey:
         point = G.multiply(x)
 
         assert point.add(k) == G.multiply(int_to_bytes_padded((bytes_to_int(x) + bytes_to_int(k)) % n))
+
+    def test_combine(self):
+        a = PrivateKey().public_key
+        b = PrivateKey().public_key
+
+        assert PublicKey.combine_keys([a, b]) == a.combine([b])