diff --git a/lib/internal/assert/assertion_error.js b/lib/internal/assert/assertion_error.js
index f12243790b0506..7f57bc57956317 100644
--- a/lib/internal/assert/assertion_error.js
+++ b/lib/internal/assert/assertion_error.js
@@ -76,7 +76,7 @@ function inspectValue(val) {
   );
 }
 
-function createErrDiff(actual, expected, operator) {
+function createErrDiff(actual, expected, operator, message = null) {
   let other = '';
   let res = '';
   let end = '';
@@ -96,47 +96,48 @@ function createErrDiff(actual, expected, operator) {
        (typeof actual === 'function' && typeof expected === 'function'))) {
     operator = 'strictEqualObject';
   }
-
   // If "actual" and "expected" fit on a single line and they are not strictly
   // equal, check further special handling.
-  if (actualLines.length === 1 && expectedLines.length === 1 &&
-    actualLines[0] !== expectedLines[0]) {
-    // Check for the visible length using the `removeColors()` function, if
-    // appropriate.
-    const c = inspect.defaultOptions.colors;
-    const actualRaw = c ? removeColors(actualLines[0]) : actualLines[0];
-    const expectedRaw = c ? removeColors(expectedLines[0]) : expectedLines[0];
-    const inputLength = actualRaw.length + expectedRaw.length;
-    // If the character length of "actual" and "expected" together is less than
-    // kMaxShortLength and if neither is an object and at least one of them is
-    // not `zero`, use the strict equal comparison to visualize the output.
-    if (inputLength <= kMaxShortLength) {
-      if ((typeof actual !== 'object' || actual === null) &&
-          (typeof expected !== 'object' || expected === null) &&
-          (actual !== 0 || expected !== 0)) { // -0 === +0
-        return `${kReadableOperator[operator]}\n\n` +
-            `${actualLines[0]} !== ${expectedLines[0]}\n`;
-      }
-    } else if (operator !== 'strictEqualObject') {
-      // If the stderr is a tty and the input length is lower than the current
-      // columns per line, add a mismatch indicator below the output. If it is
-      // not a tty, use a default value of 80 characters.
-      const maxLength = process.stderr.isTTY ? process.stderr.columns : 80;
-      if (inputLength < maxLength) {
-        while (actualRaw[i] === expectedRaw[i]) {
-          i++;
+  if (message == null) {
+    if (actualLines.length === 1 && expectedLines.length === 1 &&
+      actualLines[0] !== expectedLines[0]) {
+      // Check for the visible length using the `removeColors()` function, if
+      // appropriate.
+      const c = inspect.defaultOptions.colors;
+      const actualRaw = c ? removeColors(actualLines[0]) : actualLines[0];
+      const expectedRaw = c ? removeColors(expectedLines[0]) : expectedLines[0];
+      const inputLength = actualRaw.length + expectedRaw.length;
+      // If the character length of "actual" and "expected" together is less than
+      // kMaxShortLength and if neither is an object and at least one of them is
+      // not `zero`, use the strict equal comparison to visualize the output.
+      if (inputLength <= kMaxShortLength) {
+        if ((typeof actual !== 'object' || actual === null) &&
+            (typeof expected !== 'object' || expected === null) &&
+            (actual !== 0 || expected !== 0)) { // -0 === +0
+          return `${kReadableOperator[operator]}\n\n` +
+              `${actualLines[0]} !== ${expectedLines[0]}\n`;
         }
-        // Ignore the first characters.
-        if (i > 2) {
-          // Add position indicator for the first mismatch in case it is a
-          // single line and the input length is less than the column length.
-          indicator = `\n  ${StringPrototypeRepeat(' ', i)}^`;
-          i = 0;
+      } else if (operator !== 'strictEqualObject') {
+        // If the stderr is a tty and the input length is lower than the current
+        // columns per line, add a mismatch indicator below the output. If it is
+        // not a tty, use a default value of 80 characters.
+        const maxLength = process.stderr.isTTY ? process.stderr.columns : 80;
+        if (inputLength < maxLength) {
+          while (actualRaw[i] === expectedRaw[i]) {
+            i++;
+          }
+          // Ignore the first characters.
+          if (i > 2) {
+            // Add position indicator for the first mismatch in case it is a
+            // single line and the input length is less than the column length.
+            indicator = `\n  ${StringPrototypeRepeat(' ', i)}^`;
+            i = 0;
+          }
         }
       }
     }
   }
-
+  
   // Remove all ending lines that match (this optimizes the output for
   // readability by reducing the number of total changed lines).
   let a = actualLines[actualLines.length - 1];
@@ -154,7 +155,6 @@ function createErrDiff(actual, expected, operator) {
     a = actualLines[actualLines.length - 1];
     b = expectedLines[expectedLines.length - 1];
   }
-
   const maxLines = MathMax(actualLines.length, expectedLines.length);
   // Strict equal with identical objects that are not identical by reference.
   // E.g., assert.deepStrictEqual({ a: Symbol() }, { a: Symbol() })
@@ -174,7 +174,6 @@ function createErrDiff(actual, expected, operator) {
     return `${kReadableOperator.notIdentical}\n\n` +
            `${ArrayPrototypeJoin(actualLines, '\n')}\n`;
   }
-
   // There were at least five identical lines at the end. Mark a couple of
   // skipped.
   if (i >= 5) {
@@ -188,8 +187,8 @@ function createErrDiff(actual, expected, operator) {
 
   let printedLines = 0;
   let identical = 0;
-  const msg = kReadableOperator[operator] +
-        `\n${colors.green}+ actual${colors.white} ${colors.red}- expected${colors.white}`;
+  const error_msg = message != null ? message : kReadableOperator[operator];
+  const msg = error_msg +`\n${colors.green}+ actual${colors.white} ${colors.red}- expected${colors.white}`;
   const skippedMsg = ` ${colors.blue}...${colors.white} Lines skipped`;
 
   let lines = actualLines;
@@ -306,7 +305,6 @@ function createErrDiff(actual, expected, operator) {
              `${colors.blue}...${colors.white}`;
     }
   }
-
   return `${msg}${skipped ? skippedMsg : ''}\n${res}${other}${end}${indicator}`;
 }
 
@@ -341,7 +339,11 @@ class AssertionError extends Error {
     if (isErrorStackTraceLimitWritable()) Error.stackTraceLimit = 0;
 
     if (message != null) {
-      super(String(message));
+      if (operator === 'deepStrictEqual' || operator === 'strictEqual') {
+        super(createErrDiff(actual, expected, operator, message));
+      } else {
+        super(String(message));
+      }
     } else {
       // Reset colors on each call to make sure we handle dynamically set environment
       // variables correct.
diff --git a/test/parallel/test-assert-deep.js b/test/parallel/test-assert-deep.js
index f7489993aa60ba..0cdd1c1d92fcae 100644
--- a/test/parallel/test-assert-deep.js
+++ b/test/parallel/test-assert-deep.js
@@ -98,6 +98,26 @@ assert.deepEqual(arr, buf);
   assert.notDeepEqual(arr, arr2);
 }
 
+{
+  const foo = { foo: 1 };
+  const bar = { bar: 1 };
+  assert.throws(
+    () => assert.deepStrictEqual(foo, bar, 'objects should be equal'),
+    {
+      code: 'ERR_ASSERTION',
+      message:
+        'objects should be equal\n' +
+        '+ actual - expected\n' +
+        '\n' +
+        '  {\n' +
+        '+   foo: 1\n' +
+        '-   bar: 1\n' +
+        '  }',
+    }
+  );
+  assert.notDeepEqual(foo, bar);
+}
+
 const date = new Date('2016');
 
 class MyDate extends Date {
diff --git a/test/parallel/test-assert.js b/test/parallel/test-assert.js
index 0343e8422885ad..11a345df1bb2f1 100644
--- a/test/parallel/test-assert.js
+++ b/test/parallel/test-assert.js
@@ -372,7 +372,7 @@ assert.throws(
 assert.throws(
   () => assert.strictEqual(1, 2, 'oh no'),
   {
-    message: 'oh no',
+    message: 'oh no\n+ actual - expected\n\n+ 1\n- 2',
     generatedMessage: false
   }
 );
@@ -817,8 +817,8 @@ assert.throws(
     {
       code: 'ERR_ASSERTION',
       constructor: assert.AssertionError,
-      message: 'The expression evaluated to a falsy value:\n\n  ' +
-               "assert(\n    (Buffer.from('test') instanceof Error)\n  )\n"
+      message:  'The expression evaluated to a falsy value:\n\n' +
+                "  assert(\n    (Buffer.from('test') instanceof Error)\n  )\n",
     }
   );
   assert.throws(
@@ -826,8 +826,8 @@ assert.throws(
     {
       code: 'ERR_ASSERTION',
       constructor: assert.AssertionError,
-      message: 'The expression evaluated to a falsy value:\n\n  ' +
-               "assert(\n    (Buffer.from('test') instanceof Error)\n  )\n"
+      message:  'The expression evaluated to a falsy value:\n\n' +
+                "  assert(\n    (Buffer.from('test') instanceof Error)\n  )\n",
     }
   );
   fs.close = tmp;
@@ -921,8 +921,9 @@ assert.throws(
   {
     code: 'ERR_ASSERTION',
     constructor: assert.AssertionError,
-    message: 'The expression evaluated to a falsy value:\n\n  ' +
-             'ok(null, undefined)\n'
+    message:
+      'The expression evaluated to a falsy value:\n\n  ' +
+      'ok(null, undefined)\n',
   }
 );
 
@@ -932,8 +933,9 @@ assert.throws(
   {
     code: 'ERR_ASSERTION',
     constructor: assert.AssertionError,
-    message: 'The expression evaluated to a falsy value:\n\n  ' +
-             'assert[\'ok\']["apply"](null, [0])\n'
+    message: 
+      'The expression evaluated to a falsy value:\n\n  ' +
+      'assert[\'ok\']["apply"](null, [0])\n'
   }
 );
 
@@ -1248,7 +1250,14 @@ assert.throws(
     ),
     {
       actual,
-      message,
+      message:
+        'message\n' +
+        '+ actual - expected\n' +
+        '\n' +
+        "+ 'foobar'\n" +
+        '- {\n' +
+        "-   message: 'foobar'\n" +
+        '- }',
       operator: 'throws',
       generatedMessage: false
     }