diff --git a/changelog/3555.bugfix.rst b/changelog/3555.bugfix.rst
new file mode 100644
index 000000000..1911e1df5
--- /dev/null
+++ b/changelog/3555.bugfix.rst
@@ -0,0 +1 @@
+Fix regression in Node.add_marker by extracting the mark object of a markdecorator.
diff --git a/src/_pytest/mark/structures.py b/src/_pytest/mark/structures.py
index 7e86aee44..2b8dbf855 100644
--- a/src/_pytest/mark/structures.py
+++ b/src/_pytest/mark/structures.py
@@ -281,7 +281,14 @@ def _marked(func, mark):
 class MarkInfo(object):
     """ Marking object created by :class:`MarkDecorator` instances. """
 
-    _marks = attr.ib()
+    _marks = attr.ib(convert=list)
+
+    @_marks.validator
+    def validate_marks(self, attribute, value):
+        for item in value:
+            if not isinstance(item, Mark):
+                raise ValueError(item)
+
     combined = attr.ib(
         repr=False,
         default=attr.Factory(
diff --git a/src/_pytest/nodes.py b/src/_pytest/nodes.py
index 8d82bf606..264077f5d 100644
--- a/src/_pytest/nodes.py
+++ b/src/_pytest/nodes.py
@@ -173,10 +173,12 @@ class Node(object):
         chain.reverse()
         return chain
 
-    def add_marker(self, marker):
+    def add_marker(self, marker, append=True):
         """ dynamically add a marker object to the node.
 
         ``marker`` can be a string or pytest.mark.* instance.
+        ``append=True`` whether to append the marker,
+            if false insert at position 0
         """
         from _pytest.mark import MarkDecorator, MARK_GEN
 
@@ -185,7 +187,7 @@ class Node(object):
         elif not isinstance(marker, MarkDecorator):
             raise ValueError("is not a string or pytest.mark.* Marker")
         self.keywords[marker.name] = marker
-        self.own_markers.append(marker)
+        self.own_markers.append(marker.mark)
 
     def iter_markers(self, name=None):
         """
diff --git a/testing/test_mark.py b/testing/test_mark.py
index e96af888a..e2e7369dc 100644
--- a/testing/test_mark.py
+++ b/testing/test_mark.py
@@ -1,7 +1,7 @@
 from __future__ import absolute_import, division, print_function
 import os
 import sys
-
+import mock
 import pytest
 from _pytest.mark import (
     MarkGenerator as Mark,
@@ -9,6 +9,7 @@ from _pytest.mark import (
     transfer_markers,
     EMPTY_PARAMETERSET_OPTION,
 )
+from _pytest.nodes import Node
 
 ignore_markinfo = pytest.mark.filterwarnings(
     "ignore:MarkInfo objects:_pytest.deprecated.RemovedInPytest4Warning"
@@ -1123,3 +1124,11 @@ def test_mark_expressions_no_smear(testdir):
     passed_k, skipped_k, failed_k = reprec_keywords.countoutcomes()
     assert passed_k == 2
     assert skipped_k == failed_k == 0
+
+
+def test_addmarker_getmarker():
+    node = Node("Test", config=mock.Mock(), session=mock.Mock(), nodeid="Test")
+    node.add_marker(pytest.mark.a(1))
+    node.add_marker("b")
+    node.get_marker("a").combined
+    node.get_marker("b").combined