diff --git a/types/pretty-ms/index.d.ts b/types/pretty-ms/index.d.ts
index b1e151cd65..ca9bf663e2 100644
--- a/types/pretty-ms/index.d.ts
+++ b/types/pretty-ms/index.d.ts
@@ -1,7 +1,8 @@
-// Type definitions for pretty-ms 3.2
+// Type definitions for pretty-ms 4.0
 // Project: https://github.com/sindresorhus/pretty-ms#readme
 // Definitions by: BendingBender <https://github.com/BendingBender>
 //                 ocboogie <https://github.com/ocboogie>
+//                 silh <https://github.com/silh>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 export = prettyMs;
@@ -14,6 +15,9 @@ declare namespace prettyMs {
         msDecimalDigits?: number;
         keepDecimalsOnWholeSeconds?: boolean;
         compact?: boolean;
+        unitCount?: number;
         verbose?: boolean;
+        separateMs?: boolean;
+        formatSubMs?: boolean;
     }
 }
diff --git a/types/pretty-ms/pretty-ms-tests.ts b/types/pretty-ms/pretty-ms-tests.ts
index ae5e8120b2..bb5e8a69ec 100644
--- a/types/pretty-ms/pretty-ms-tests.ts
+++ b/types/pretty-ms/pretty-ms-tests.ts
@@ -7,4 +7,7 @@ str = prettyMs(1335669000, {verbose: true});
 str = prettyMs(1335669000, {keepDecimalsOnWholeSeconds: true});
 str = prettyMs(1335669000, {secDecimalDigits: 1});
 str = prettyMs(1335669000, {msDecimalDigits: 2});
+str = prettyMs(1335669000, {unitCount: 2});
+str = prettyMs(1335669000, {separateMs: true});
+str = prettyMs(1335669000, {formatSubMs: true});
 str = prettyMs(new Date(2014, 0, 1, 10, 40).getTime() - new Date(2014, 0, 1, 10, 5).getTime());
diff --git a/types/pretty-ms/v3/index.d.ts b/types/pretty-ms/v3/index.d.ts
new file mode 100644
index 0000000000..b1e151cd65
--- /dev/null
+++ b/types/pretty-ms/v3/index.d.ts
@@ -0,0 +1,19 @@
+// Type definitions for pretty-ms 3.2
+// Project: https://github.com/sindresorhus/pretty-ms#readme
+// Definitions by: BendingBender <https://github.com/BendingBender>
+//                 ocboogie <https://github.com/ocboogie>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+export = prettyMs;
+
+declare function prettyMs(input: number, options?: prettyMs.PrettyMsOptions): string;
+
+declare namespace prettyMs {
+    interface PrettyMsOptions {
+        secDecimalDigits?: number;
+        msDecimalDigits?: number;
+        keepDecimalsOnWholeSeconds?: boolean;
+        compact?: boolean;
+        verbose?: boolean;
+    }
+}
diff --git a/types/pretty-ms/v3/pretty-ms-tests.ts b/types/pretty-ms/v3/pretty-ms-tests.ts
new file mode 100644
index 0000000000..ae5e8120b2
--- /dev/null
+++ b/types/pretty-ms/v3/pretty-ms-tests.ts
@@ -0,0 +1,10 @@
+import prettyMs = require('pretty-ms');
+
+let str: string;
+str = prettyMs(133);
+str = prettyMs(1337, {compact: true});
+str = prettyMs(1335669000, {verbose: true});
+str = prettyMs(1335669000, {keepDecimalsOnWholeSeconds: true});
+str = prettyMs(1335669000, {secDecimalDigits: 1});
+str = prettyMs(1335669000, {msDecimalDigits: 2});
+str = prettyMs(new Date(2014, 0, 1, 10, 40).getTime() - new Date(2014, 0, 1, 10, 5).getTime());
diff --git a/types/pretty-ms/v3/tsconfig.json b/types/pretty-ms/v3/tsconfig.json
new file mode 100644
index 0000000000..5d4f2d4c31
--- /dev/null
+++ b/types/pretty-ms/v3/tsconfig.json
@@ -0,0 +1,28 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "strictFunctionTypes": true,
+        "baseUrl": "../../",
+        "typeRoots": [
+            "../../"
+        ],
+        "paths": {
+            "pretty-ms": [
+                "pretty-ms/v3"
+            ]
+        },
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "pretty-ms-tests.ts"
+    ]
+}
diff --git a/types/pretty-ms/v3/tslint.json b/types/pretty-ms/v3/tslint.json
new file mode 100644
index 0000000000..3db14f85ea
--- /dev/null
+++ b/types/pretty-ms/v3/tslint.json
@@ -0,0 +1 @@
+{ "extends": "dtslint/dt.json" }