diff --git a/poetry/packages/package.py b/poetry/packages/package.py
index 4b39bb9eb5c..4a29318c25a 100644
--- a/poetry/packages/package.py
+++ b/poetry/packages/package.py
@@ -163,11 +163,10 @@ def _get_author(self):  # type: () -> dict
         m = AUTHOR_REGEX.match(self._authors[0])
 
         if m is None:
-            logger.warning(
+            raise ValueError(
                 "Invalid author string. Must be in the format: "
                 "John Smith <john@example.com>"
             )
-            return {"name": None, "email": None}
 
         name = m.group("name")
         email = m.group("email")
@@ -181,11 +180,10 @@ def _get_maintainer(self):  # type: () -> dict
         m = AUTHOR_REGEX.match(self._maintainers[0])
 
         if m is None:
-            logger.warning(
+            raise ValueError(
                 "Invalid maintainer string. Must be in the format: "
                 "John Smith <john@example.com>"
             )
-            return {"name": None, "email": None}
 
         name = m.group("name")
         email = m.group("email")
diff --git a/tests/packages/test_package.py b/tests/packages/test_package.py
index c25e15cde48..5ac0b56efa5 100644
--- a/tests/packages/test_package.py
+++ b/tests/packages/test_package.py
@@ -17,9 +17,18 @@ def test_package_authors():
     assert package.author_name == "John Doe"
     assert package.author_email is None
 
+
+def test_package_authors_invalid():
+    package = Package("foo", "0.1.0")
+
     package.authors.insert(0, "<John Doe")
-    assert package.author_name is None
-    assert package.author_email is None
+    with pytest.raises(ValueError) as e:
+        package.author_name
+
+    assert (
+        str(e.value)
+        == "Invalid author string. Must be in the format: John Smith <john@example.com>"
+    )
 
 
 @pytest.mark.parametrize("category", ["main", "dev"])