diff --git a/packages/webpack/src/config/client.js b/packages/webpack/src/config/client.js
index dc1c9078dc..46a484613b 100644
--- a/packages/webpack/src/config/client.js
+++ b/packages/webpack/src/config/client.js
@@ -182,9 +182,9 @@ export default class WebpackClientConfig extends WebpackBaseConfig {
       `${querystring.stringify(hotMiddlewareClientOptions)}&path=${clientPath}`.replace(/\/\//g, '/')
 
     // Entry points
-    config.entry = {
+    config.entry = Object.assign({}, config.entry, {
       app: [path.resolve(buildDir, 'client.js')]
-    }
+    })
 
     // Add HMR support
     if (this.dev) {
diff --git a/packages/webpack/src/config/server.js b/packages/webpack/src/config/server.js
index 548267834b..25a30c37f4 100644
--- a/packages/webpack/src/config/server.js
+++ b/packages/webpack/src/config/server.js
@@ -69,9 +69,9 @@ export default class WebpackServerConfig extends WebpackBaseConfig {
     Object.assign(config, {
       target: 'node',
       node: false,
-      entry: {
+      entry: Object.assign({}, config.entry, {
         app: [path.resolve(this.buildContext.options.buildDir, 'server.js')]
-      },
+      }),
       output: Object.assign({}, config.output, {
         filename: 'server.js',
         libraryTarget: 'commonjs2'