How can I run a command in zsh without pushing it onto the current session's history?

view story

http://unix.stackexchange.com – Both bash and zsh support a shorthand of not placing a command in history if you prepend it with a space. This works great across sessions (if you've setopt histignorespace). However, the command is still in the current session's history. How can I avoid placing a command in the current session's history (or remove if after executing it)? (HowTos)