diff --git a/types/optimize-css-assets-webpack-plugin/index.d.ts b/types/optimize-css-assets-webpack-plugin/index.d.ts
index d79c14e809..1a55346d3b 100644
--- a/types/optimize-css-assets-webpack-plugin/index.d.ts
+++ b/types/optimize-css-assets-webpack-plugin/index.d.ts
@@ -1,6 +1,7 @@
-// Type definitions for optimize-css-assets-webpack-plugin 1.3
+// Type definitions for optimize-css-assets-webpack-plugin 5.0
 // Project: http://github.com/nmfr/optimize-css-assets-webpack-plugin
 // Definitions by: Armando Meziat <https://github.com/odnamrataizem>
+//                 Spencer Miskoviak <https://github.com/skovy>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
@@ -9,14 +10,47 @@ import { Plugin } from 'webpack';
 export = OptimizeCssAssetsPlugin;
 
 declare namespace OptimizeCssAssetsPlugin {
-	interface Options {
-		assetNameRegExp?: RegExp;
-		cssProcessor?: any;
-		cssProcessorOptions?: any;
-		canPrint?: boolean;
-	}
+    interface Options {
+        /**
+         * A regular expression that indicates the names of the assets that should
+         * be optimized \ minimized. The regular expression provided is run against
+         * the filenames of the files exported by the `ExtractTextPlugin` instances
+         * in your configuration, not the filenames of your source CSS files
+         *
+         * @default /\.css$/g
+         */
+        assetNameRegExp?: RegExp;
+        /**
+         * The CSS processor used to optimize \ minimize the CSS. This should be a
+         * function that follows `cssnano.process` interface (receives a CSS and
+         * options parameters and returns a Promise).
+         *
+         * @default cssnano
+         */
+        cssProcessor?: {
+            proccess: (css: string, options?: object) => PromiseLike<any>;
+        };
+        /**
+         * The options passed to the `cssProcessor`.
+         *
+         * @default {}
+         */
+        cssProcessorOptions?: object;
+        /**
+         * The plugin options passed to the `cssProcessor`.
+         *
+         * @default {}
+         */
+        cssProcessorPluginOptions?: object;
+        /**
+         * A boolean indicating if the plugin can print messages to the console.
+         *
+         * @default true
+         */
+        canPrint?: boolean;
+    }
 }
 
 declare class OptimizeCssAssetsPlugin extends Plugin {
-	constructor(options?: OptimizeCssAssetsPlugin.Options);
+    constructor(options?: OptimizeCssAssetsPlugin.Options);
 }
diff --git a/types/optimize-css-assets-webpack-plugin/optimize-css-assets-webpack-plugin-tests.ts b/types/optimize-css-assets-webpack-plugin/optimize-css-assets-webpack-plugin-tests.ts
index 0dd1531313..55da8da2bd 100644
--- a/types/optimize-css-assets-webpack-plugin/optimize-css-assets-webpack-plugin-tests.ts
+++ b/types/optimize-css-assets-webpack-plugin/optimize-css-assets-webpack-plugin-tests.ts
@@ -1,6 +1,24 @@
-import OptimizeCssAssets = require('optimize-css-assets-webpack-plugin');
+import webpack = require('webpack');
+import OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin');
 
-const ocap: OptimizeCssAssets = new OptimizeCssAssets({
-	assetNameRegExp: /\.min\.css$/,
-	canPrint: true
-});
+let configuration: webpack.Configuration;
+
+configuration = {
+  plugins: [new OptimizeCssAssetsPlugin()],
+};
+
+configuration = {
+  plugins: [
+    new OptimizeCssAssetsPlugin({
+      assetNameRegExp: /\.min\.css$/,
+      cssProcessor: require('cssnano'),
+      cssProcessorOptions: {
+        map: false,
+      },
+      cssProcessorPluginOptions: {
+        preset: ['default', { discardComments: { removeAll: true } }],
+      },
+      canPrint: true,
+    }),
+  ],
+};