diff --git a/moto/dynamodb2/responses.py b/moto/dynamodb2/responses.py
index 3c7e7ffc2..493e17833 100644
--- a/moto/dynamodb2/responses.py
+++ b/moto/dynamodb2/responses.py
@@ -20,6 +20,17 @@ def has_empty_keys_or_values(_dict):
     )
 
 
+def get_empty_str_error():
+    er = 'com.amazonaws.dynamodb.v20111205#ValidationException'
+    return (400,
+            {'server': 'amazon.com'},
+            dynamo_json_dump({'__type': er,
+                              'message': ('One or more parameter values were '
+                                          'invalid: An AttributeValue may not '
+                                          'contain an empty string')}
+                             ))
+
+
 class DynamoHandler(BaseResponse):
 
     def get_endpoint_name(self, headers):
@@ -174,14 +185,7 @@ class DynamoHandler(BaseResponse):
         item = self.body['Item']
 
         if has_empty_keys_or_values(item):
-            er = 'com.amazonaws.dynamodb.v20111205#ValidationException'
-            return (400,
-                {'server': 'amazon.com'},
-                dynamo_json_dump({'__type': er,
-                                'message': ('One or more parameter values were '
-                                            'invalid: An AttributeValue may not '
-                                            'contain an empty string')}
-                                 ))
+            return get_empty_str_error()
 
         overwrite = 'Expected' not in self.body
         if not overwrite:
@@ -523,6 +527,7 @@ class DynamoHandler(BaseResponse):
         return dynamo_json_dump(item_dict)
 
     def update_item(self):
+
         name = self.body['TableName']
         key = self.body['Key']
         update_expression = self.body.get('UpdateExpression')
@@ -533,6 +538,9 @@ class DynamoHandler(BaseResponse):
             'ExpressionAttributeValues', {})
         existing_item = self.dynamodb_backend.get_item(name, key)
 
+        if has_empty_keys_or_values(expression_attribute_values):
+            return get_empty_str_error()
+
         if 'Expected' in self.body:
             expected = self.body['Expected']
         else:
diff --git a/tests/test_dynamodb2/test_dynamodb.py b/tests/test_dynamodb2/test_dynamodb.py
index ab8f25856..243de2701 100644
--- a/tests/test_dynamodb2/test_dynamodb.py
+++ b/tests/test_dynamodb2/test_dynamodb.py
@@ -201,6 +201,48 @@ def test_item_add_empty_string_exception():
     )
 
 
+@requires_boto_gte("2.9")
+@mock_dynamodb2
+def test_update_item_with_empty_string_exception():
+    name = 'TestTable'
+    conn = boto3.client('dynamodb',
+                        region_name='us-west-2',
+                        aws_access_key_id="ak",
+                        aws_secret_access_key="sk")
+    conn.create_table(TableName=name,
+                      KeySchema=[{'AttributeName':'forum_name','KeyType':'HASH'}],
+                      AttributeDefinitions=[{'AttributeName':'forum_name','AttributeType':'S'}],
+                      ProvisionedThroughput={'ReadCapacityUnits':5,'WriteCapacityUnits':5})
+
+    conn.put_item(
+        TableName=name,
+        Item={
+            'forum_name': { 'S': 'LOLCat Forum' },
+            'subject': { 'S': 'Check this out!' },
+            'Body': { 'S': 'http://url_to_lolcat.gif'},
+            'SentBy': { 'S': "test" },
+            'ReceivedTime': { 'S': '12/9/2011 11:36:03 PM'},
+        }
+    )
+
+    with assert_raises(ClientError) as ex:
+        conn.update_item(
+            TableName=name,
+            Key={
+                'forum_name': { 'S': 'LOLCat Forum'},
+            },
+            UpdateExpression='set Body=:Body',
+            ExpressionAttributeValues={
+                ':Body': {'S': ''}
+            })
+
+    ex.exception.response['Error']['Code'].should.equal('ValidationException')
+    ex.exception.response['ResponseMetadata']['HTTPStatusCode'].should.equal(400)
+    ex.exception.response['Error']['Message'].should.equal(
+        'One or more parameter values were invalid: An AttributeValue may not contain an empty string'
+    )
+
+
 @requires_boto_gte("2.9")
 @mock_dynamodb2
 def test_query_invalid_table():