diff --git a/nbs/timegpt.ipynb b/nbs/timegpt.ipynb
index 673fb095..f682305e 100644
--- a/nbs/timegpt.ipynb
+++ b/nbs/timegpt.ipynb
@@ -259,6 +259,14 @@
     "                df.index.name = time_col\n",
     "            df = df.reset_index()\n",
     "        else:\n",
+    "            if hasattr(df.index, \"name\"):\n",
+    "                if df.index.name == self.time_col:\n",
+    "                    try:\n",
+    "                        df.index = pd.to_datetime(df.index)\n",
+    "                        main_logger.info(\"Using datetime index as time column\")\n",
+    "                    except:\n",
+    "                        raise ValueError(f\"Dataframe index {self.time_col} is not of date type\")\n",
+    "                    df=df.reset_index()\n",
     "            self.freq = self.base_freq\n",
     "        renamer = {\n",
     "            self.id_col: 'unique_id',\n",
diff --git a/nixtlats/timegpt.py b/nixtlats/timegpt.py
index 71f1dcd6..427c0cff 100644
--- a/nixtlats/timegpt.py
+++ b/nixtlats/timegpt.py
@@ -197,6 +197,16 @@ def transform_inputs(self, df: pd.DataFrame, X_df: pd.DataFrame):
                 df.index.name = time_col
             df = df.reset_index()
         else:
+            if hasattr(df.index, "name"):
+                if df.index.name == self.time_col:
+                    try:
+                        df.index = pd.to_datetime(df.index)
+                        main_logger.info("Using datetime index as time column")
+                    except:
+                        raise ValueError(
+                            f"Dataframe index {self.time_col} is not of date type"
+                        )
+                    df = df.reset_index()
             self.freq = self.base_freq
         renamer = {
             self.id_col: "unique_id",