diff --git a/lib/core.js b/lib/core.js
index 570fdd3..b64b063 100644
--- a/lib/core.js
+++ b/lib/core.js
@@ -52,7 +52,7 @@ module.exports = app => {
           return this._emit(event, data, ctx);
         }
 
-        const serializedContext = typeof ctx.toJSON === 'function' ? ctx.toJSON() : ctx;
+        const serializedContext = ctx && typeof ctx.toJSON === 'function' ? ctx.toJSON() : ctx;
         const context = ctx && (ctx.app === app || ctx.service === service)
           ? _.omit(serializedContext, 'app', 'service', 'self')
           : serializedContext;