diff --git a/rich/table.py b/rich/table.py
index 2f73a9c8..0fe6755a 100644
--- a/rich/table.py
+++ b/rich/table.py
@@ -138,8 +138,8 @@ class Table(JupyterMixin):
         border_style: StyleType = None,
         title_style: StyleType = None,
         caption_style: StyleType = None,
-        title_justify: str = "center",
-        caption_justify: str = "center",
+        title_justify: "JustifyMethod" = "center",
+        caption_justify: "JustifyMethod" = "center",
     ) -> None:
 
         self.columns: List[Column] = []
@@ -387,7 +387,7 @@ class Table(JupyterMixin):
         render_options = options.update(width=table_width)
 
         def render_annotation(
-            text: TextType, style: StyleType, justify: str = "center"
+            text: TextType, style: StyleType, justify: JustifyMethod = "center"
         ) -> "RenderResult":
             render_text = (
                 console.render_str(text, style=style) if isinstance(text, str) else text
diff --git a/rich/tabulate.py b/rich/tabulate.py
index bb87280b..ef668c9e 100644
--- a/rich/tabulate.py
+++ b/rich/tabulate.py
@@ -1,20 +1,20 @@
 from collections.abc import Mapping
+from typing import Optional
 
+from rich.console import JustifyMethod
 
 from . import box
 from .highlighter import ReprHighlighter
 from .pretty import Pretty
 from .table import Table
 
-_NOT_PROVIDED = object()
-
 
 def tabulate_mapping(
     mapping: Mapping,
     title: str = None,
     caption: str = None,
-    title_justify: str = _NOT_PROVIDED,
-    caption_justify: str = _NOT_PROVIDED,
+    title_justify: Optional[JustifyMethod] = None,
+    caption_justify: Optional[JustifyMethod] = None,
 ) -> Table:
     """Generate a simple table from a mapping.
 
@@ -37,9 +37,9 @@ def tabulate_mapping(
     )
     table.title = title
     table.caption = caption
-    if title_justify is not _NOT_PROVIDED:
+    if title_justify is not None:
         table.title_justify = title_justify
-    if caption_justify is not _NOT_PROVIDED:
+    if caption_justify is not None:
         table.caption_justify = caption_justify
     highlighter = ReprHighlighter()
     for key, value in mapping.items():