diff --git a/CHANGELOG.md b/CHANGELOG.md
index 530c0b3e..edf70259 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## v0.15.1 (2022-03-23)
+
+* Added `ensure_has_html` method for `TextMessageEventContent` to generate
+  a HTML `formatted_body` from the plaintext `body` correctly (i.e. escaping
+  HTML and replacing newlines).
+
 ## v0.15.0 (2022-03-16)
 
 * **Breaking change** Removed Python 3.7 support.
diff --git a/mautrix/__init__.py b/mautrix/__init__.py
index 401a2d72..2446a694 100644
--- a/mautrix/__init__.py
+++ b/mautrix/__init__.py
@@ -1,4 +1,4 @@
-__version__ = "0.15.0"
+__version__ = "0.15.1"
 __author__ = "Tulir Asokan <tulir@maunium.net>"
 __all__ = [
     "api",
diff --git a/mautrix/types/event/message.py b/mautrix/types/event/message.py
index 2fcbcdf9..6285b2e0 100644
--- a/mautrix/types/event/message.py
+++ b/mautrix/types/event/message.py
@@ -342,15 +342,18 @@ def set_reply(
         super().set_reply(reply_to)
         if isinstance(reply_to, str):
             return
-        if not self.formatted_body or len(self.formatted_body) == 0 or self.format != Format.HTML:
-            self.format = Format.HTML
-            self.formatted_body = escape(self.body).replace("\n", "<br/>")
         if isinstance(reply_to, MessageEvent):
+            self.ensure_has_html()
             self.formatted_body = (
                 reply_to.make_reply_fallback_html(displayname) + self.formatted_body
             )
             self.body = reply_to.make_reply_fallback_text(displayname) + self.body
 
+    def ensure_has_html(self) -> None:
+        if not self.formatted_body or self.format != Format.HTML:
+            self.format = Format.HTML
+            self.formatted_body = escape(self.body).replace("\n", "<br/>")
+
     def formatted(self, format: Format) -> Optional[str]:
         if self.format == format:
             return self.formatted_body