diff --git a/pure.zsh b/pure.zsh
index b0ecfbf..1db1813 100644
--- a/pure.zsh
+++ b/pure.zsh
@@ -123,6 +123,9 @@ prompt_pure_string_length_to_var() {
 }
 
 prompt_pure_preprompt_render() {
+	# make sure prompt_subst is unset to prevent parameter expansion in prompt
+	setopt local_options no_prompt_subst
+
 	# check that no command is currently running, the preprompt will otherwise be rendered in the wrong place
 	[[ -n ${prompt_pure_cmd_timestamp+x} && "$1" != "precmd" ]] && return