diff --git a/kats/detectors/prophet_detector.py b/kats/detectors/prophet_detector.py
index db60baade..1f7a3e6d6 100644
--- a/kats/detectors/prophet_detector.py
+++ b/kats/detectors/prophet_detector.py
@@ -138,10 +138,27 @@ class SeasonalityTypes(Enum):
 EMPTY_LIST: List[SeasonalityTypes] = []
 
 
+def to_seasonality(seasonality: Union[str, SeasonalityTypes]) -> SeasonalityTypes:
+    if isinstance(seasonality, str):
+        try:
+            return SeasonalityTypes[seasonality.upper()]
+        except KeyError:
+            raise ValueError(
+                f"Invalid seasonality type: {seasonality}. Valid types are: {list(SeasonalityTypes)}"
+            )
+    elif isinstance(seasonality, SeasonalityTypes):
+        return seasonality
+    else:
+        raise ValueError(
+            f"Expected string or SeasonalityTypes, got {type(seasonality)} instead"
+        )
+
+
 def seasonalities_to_dict(
     seasonalities: Union[
         SeasonalityTypes,
         List[SeasonalityTypes],
+        List[str],
         Dict[SeasonalityTypes, Union[bool, str]],
     ]
 ) -> Dict[SeasonalityTypes, Union[bool, str]]:
@@ -149,7 +166,9 @@ def seasonalities_to_dict(
     if isinstance(seasonalities, SeasonalityTypes):
         seasonalities = {seasonalities: True}
     elif isinstance(seasonalities, list):
-        seasonalities = {seasonality: True for seasonality in seasonalities}
+        seasonalities = {
+            to_seasonality(seasonality): True for seasonality in seasonalities
+        }
     elif seasonalities is None:
         seasonalities = {}
     return seasonalities
@@ -253,6 +272,7 @@ def __init__(
             Union[
                 SeasonalityTypes,
                 List[SeasonalityTypes],
+                List[str],
                 Dict[SeasonalityTypes, Union[bool, str]],
             ]
         ] = EMPTY_LIST,
diff --git a/kats/tests/detectors/test_prophet_detector.py b/kats/tests/detectors/test_prophet_detector.py
index 0374684c4..bab8bf3f7 100644
--- a/kats/tests/detectors/test_prophet_detector.py
+++ b/kats/tests/detectors/test_prophet_detector.py
@@ -5,6 +5,7 @@
 
 import random
 from datetime import timedelta
+from typing import Union
 from unittest import TestCase
 
 import numpy as np
@@ -17,6 +18,7 @@
     ProphetScoreFunction,
     ProphetTrendDetectorModel,
     SeasonalityTypes,
+    to_seasonality,
 )
 from kats.utils.simulator import Simulator
 from parameterized.parameterized import parameterized
@@ -872,3 +874,21 @@ def test_pmm_use_case(self) -> None:
         self.assertEqual(
             response_wo_historical_data.scores.value.shape, hist_ts.value.shape
         )
+
+    # pyre-fixme[56]: Pyre was not able to infer the type of the decorator `parameter...
+    @parameterized.expand(
+        [
+            ("day", SeasonalityTypes.DAY),
+            ("week", SeasonalityTypes.WEEK),
+            ("weekend", SeasonalityTypes.WEEKEND),
+            ("year", SeasonalityTypes.YEAR),
+            (SeasonalityTypes.DAY, SeasonalityTypes.DAY),
+            (SeasonalityTypes.WEEK, SeasonalityTypes.WEEK),
+            (SeasonalityTypes.WEEKEND, SeasonalityTypes.WEEKEND),
+            (SeasonalityTypes.YEAR, SeasonalityTypes.YEAR),
+        ]
+    )
+    def test_to_seasonality(
+        self, actual: Union[str, SeasonalityTypes], expected: SeasonalityTypes
+    ) -> None:
+        self.assertEqual(to_seasonality(actual), expected)