diff --git a/plugins/virtualenv/virtualenv.plugin.zsh b/plugins/virtualenv/virtualenv.plugin.zsh
index e250eb63e..3041475ed 100644
--- a/plugins/virtualenv/virtualenv.plugin.zsh
+++ b/plugins/virtualenv/virtualenv.plugin.zsh
@@ -1,6 +1,6 @@
 function virtualenv_prompt_info(){
   [[ -n ${VIRTUAL_ENV} ]] || return
-  echo "${ZSH_THEME_VIRTUALENV_PREFIX:=[}${VIRTUAL_ENV:t}${ZSH_THEME_VIRTUALENV_SUFFIX:=]}"
+  echo "${ZSH_THEME_VIRTUALENV_PREFIX=[}${VIRTUAL_ENV:t}${ZSH_THEME_VIRTUALENV_SUFFIX=]}"
 }
 
 # disables prompt mangling in virtual_env/bin/activate