diff --git a/lib/webmock/http_lib_adapters/em_http_request.rb b/lib/webmock/http_lib_adapters/em_http_request.rb
index 46763da5a..a673a13f9 100644
--- a/lib/webmock/http_lib_adapters/em_http_request.rb
+++ b/lib/webmock/http_lib_adapters/em_http_request.rb
@@ -92,7 +92,7 @@ def build_request_signature
           uri.userinfo = userinfo
         end
 
-        uri.query = encode_query(@req.uri, options[:query])[2..-1]
+        uri.query = encode_query(@req.uri, options[:query]).slice(/\?(.*)/, 1)
 
         WebMock::RequestSignature.new(
           method.downcase.to_sym,