diff --git a/lib/websocket-client-simple/client.rb b/lib/websocket-client-simple/client.rb
index 128f523..f454fd8 100644
--- a/lib/websocket-client-simple/client.rb
+++ b/lib/websocket-client-simple/client.rb
@@ -26,6 +26,8 @@ def connect(url, options={})
             cert_store = OpenSSL::X509::Store.new
             cert_store.set_default_paths
             ctx.cert_store = cert_store
+            ctx.cert = OpenSSL::X509::Certificate.new(File.read(options[:cert_chain_file])) || nil
+            ctx.key = OpenSSL::PKey::RSA.new(File.read(options[:private_key_file])) || nil
             @socket = ::OpenSSL::SSL::SSLSocket.new(@socket, ctx)
             @socket.connect
           end