diff --git a/discord/http.py b/discord/http.py
index b247f9342..8f1d4e3f5 100644
--- a/discord/http.py
+++ b/discord/http.py
@@ -4249,7 +4249,7 @@ class HTTPClient:
     def get_trial_offer(self) -> Response[promotions.TrialOffer]:
         return self.request(Route('GET', '/users/@me/billing/user-trial-offer'))
 
-    def ack_trial_offer(self, trial_id: Snowflake) -> Response[None]:
+    def ack_trial_offer(self, trial_id: Snowflake) -> Response[promotions.TrialOffer]:
         return self.request(Route('POST', '/users/@me/billing/user-trial-offer/{trial_id}/ack', trial_id=trial_id))
 
     def get_pricing_promotion(self) -> Response[promotions.WrappedPricingPromotion]:
diff --git a/discord/promotions.py b/discord/promotions.py
index 6f7337662..f039ea86a 100644
--- a/discord/promotions.py
+++ b/discord/promotions.py
@@ -224,8 +224,8 @@ class TrialOffer(Hashable):
     ----------
     id: :class:`int`
         The ID of the trial offer.
-    expires_at: :class:`datetime.datetime`
-        When the trial offer expires.
+    expires_at: Optional[:class:`datetime.datetime`]
+        When the trial offer expires, if it has been acknowledged.
     trial_id: :class:`int`
         The ID of the trial.
     trial: :class:`SubscriptionTrial`
@@ -242,15 +242,24 @@ class TrialOffer(Hashable):
 
     def __init__(self, *, data: TrialOfferPayload, state: ConnectionState) -> None:
         self._state = state
+        self._update(data)
 
+    def _update(self, data: TrialOfferPayload) -> None:
         self.id: int = int(data['id'])
-        self.expires_at: datetime = parse_time(data['expires_at'])
+        self.expires_at: Optional[datetime] = parse_time(data.get('expires_at'))
         self.trial_id: int = int(data['trial_id'])
         self.trial: SubscriptionTrial = SubscriptionTrial(data['subscription_trial'])
 
     def __repr__(self) -> str:
         return f'<TrialOffer id={self.id} trial={self.trial!r}>'
 
+    def is_acked(self) -> bool:
+        """:class:`bool`: Checks if the trial offer has been acknowledged.
+
+        .. versionadded:: 2.1
+        """
+        return self.expires_at is not None
+
     async def ack(self) -> None:
         """|coro|
 
@@ -261,7 +270,8 @@ class TrialOffer(Hashable):
         HTTPException
             Acknowledging the trial offer failed.
         """
-        await self._state.http.ack_trial_offer(self.id)
+        data = await self._state.http.ack_trial_offer(self.id)
+        self._update(data)
 
 
 class PricingPromotion:
diff --git a/discord/types/promotions.py b/discord/types/promotions.py
index e49d3877e..bdcb89f6a 100644
--- a/discord/types/promotions.py
+++ b/discord/types/promotions.py
@@ -57,7 +57,7 @@ class ClaimedPromotion(TypedDict):
 
 class TrialOffer(TypedDict):
     id: Snowflake
-    expires_at: str
+    expires_at: Optional[str]
     trial_id: Snowflake
     subscription_trial: SubscriptionTrial