diff --git a/pkg/api/unversioned/group_version.go b/pkg/api/unversioned/group_version.go
new file mode 100644
index 0000000000..acbbc16600
--- /dev/null
+++ b/pkg/api/unversioned/group_version.go
@@ -0,0 +1,75 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package unversioned
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+// TODO: We need to remove the GroupVersion in types.go. We use the name GroupAndVersion here temporarily.
+type GroupAndVersion struct {
+	Group   string
+	Version string
+}
+
+func (gv *GroupAndVersion) String() string {
+	// special case of "v1" for backward compatibility
+	if gv.Group == "" {
+		return gv.Version
+	} else {
+		return gv.Group + "/" + gv.Version
+	}
+}
+
+func ParseGroupVersion(gv string) (GroupAndVersion, error) {
+	s := strings.Split(gv, "/")
+	// "v1" is the only special case. Otherwise GroupVersion is expected to contain
+	// one "/" dividing the string into two parts.
+	if len(s) == 1 && gv == "v1" {
+		return GroupAndVersion{"", "v1"}, nil
+	} else if len(s) == 2 {
+		return GroupAndVersion{s[0], s[1]}, nil
+	} else {
+		return GroupAndVersion{}, fmt.Errorf("Unexpected GroupVersion string: %v", gv)
+	}
+}
+
+// MarshalJSON implements the json.Marshaller interface.
+func (gv GroupAndVersion) MarshalJSON() ([]byte, error) {
+	s := gv.String()
+	if strings.Count(s, "/") > 1 {
+		return []byte{}, fmt.Errorf("illegal GroupVersion %v: contains more than one /", s)
+	}
+	return json.Marshal(s)
+}
+
+// UnmarshalJSON implements the json.Unmarshaller interface.
+func (gv *GroupAndVersion) UnmarshalJSON(value []byte) error {
+	var s string
+	if err := json.Unmarshal(value, &s); err != nil {
+		return err
+	}
+	parsed, err := ParseGroupVersion(s)
+	if err != nil {
+		return err
+	}
+	gv.Group = parsed.Group
+	gv.Version = parsed.Version
+	return nil
+}
diff --git a/pkg/api/unversioned/group_version_test.go b/pkg/api/unversioned/group_version_test.go
new file mode 100644
index 0000000000..daf1c3da77
--- /dev/null
+++ b/pkg/api/unversioned/group_version_test.go
@@ -0,0 +1,68 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package unversioned
+
+import (
+	"encoding/json"
+	"reflect"
+	"testing"
+)
+
+type GroupVersionHolder struct {
+	GV GroupAndVersion `json:"val"`
+}
+
+func TestGroupVersionUnmarshalJSON(t *testing.T) {
+	cases := []struct {
+		input  []byte
+		expect GroupAndVersion
+	}{
+		{[]byte(`{"val": "v1"}`), GroupAndVersion{"", "v1"}},
+		{[]byte(`{"val": "extensions/v1beta1"}`), GroupAndVersion{"extensions", "v1beta1"}},
+	}
+
+	for _, c := range cases {
+		var result GroupVersionHolder
+		if err := json.Unmarshal([]byte(c.input), &result); err != nil {
+			t.Errorf("Failed to unmarshal input '%v': %v", c.input, err)
+		}
+		if !reflect.DeepEqual(result.GV, c.expect) {
+			t.Errorf("Failed to unmarshal input '%s': expected %+v, got %+v", c.input, c.expect, result.GV)
+		}
+	}
+}
+
+func TestGroupVersionMarshalJSON(t *testing.T) {
+	cases := []struct {
+		input  GroupAndVersion
+		expect []byte
+	}{
+		{GroupAndVersion{"", "v1"}, []byte(`{"val":"v1"}`)},
+		{GroupAndVersion{"extensions", "v1beta1"}, []byte(`{"val":"extensions/v1beta1"}`)},
+	}
+
+	for _, c := range cases {
+		input := GroupVersionHolder{c.input}
+		result, err := json.Marshal(&input)
+		if err != nil {
+			t.Errorf("Failed to marshal input '%v': %v", input, err)
+		}
+		if !reflect.DeepEqual(result, c.expect) {
+			t.Errorf("Failed to marshal input '%+v': expected: %s, got: %s", input, c.expect, result)
+		}
+	}
+}