diff --git a/History.md b/History.md
index e9dfe33d7..1905e22f8 100644
--- a/History.md
+++ b/History.md
@@ -13,6 +13,7 @@
 ## Fixes
 
 - fix: Do not response Content-Length if Transfer-Encoding is defined #1562 @charlyzeng
+- fix: Set body to `null` if `ctx.type = json` and `ctx.body = null` #1059 @likegun
 
 2.13.1 / 2021-01-04
 ==================
diff --git a/__tests__/response/length.js b/__tests__/response/length.js
index 1e58f42a4..7ca9ef891 100644
--- a/__tests__/response/length.js
+++ b/__tests__/response/length.js
@@ -27,6 +27,9 @@ describe('res.length', () => {
       it('should return a number', () => {
         const res = response()
 
+        res.body = null
+        assert.strictEqual(res.length, undefined)
+
         res.body = 'foo'
         res.remove('Content-Length')
         assert.strictEqual(res.length, 3)
@@ -63,4 +66,16 @@ describe('res.length', () => {
       })
     })
   })
+
+  describe('and a .type is set to json', () => {
+    describe('and a .body is set to null', () => {
+      it('should return a number', () => {
+        const res = response()
+
+        res.type = 'json'
+        res.body = null
+        assert.strictEqual(res.length, 4)
+      })
+    })
+  })
 })
diff --git a/lib/response.js b/lib/response.js
index 8546c632b..d15ecd5c2 100644
--- a/lib/response.js
+++ b/lib/response.js
@@ -137,7 +137,13 @@ module.exports = {
 
     // no content
     if (val == null) {
-      if (!statuses.empty[this.status]) this.status = 204
+      if (!statuses.empty[this.status]) {
+        if (this.type === 'application/json') {
+          this._body = 'null'
+          return
+        }
+        this.status = 204
+      }
       if (val === null) this._explicitNullBody = true
       this.remove('Content-Type')
       this.remove('Content-Length')