GPG Agent has the ability to act as a SSH Agent. This allows the use of Authentication keys on Smartcards to be used with SSH as well.
First we need to enable SSH support in GPG Agent,
echo "enable-ssh-support" >> ~/.gnupg/gpg-agent.conf
Then we need to specify an environmental variable for the SSH Daemon to use GPG Agent
echo "export SSH_AUTH_SOCK=$(gpgconf --list-dirs agent-ssh-socket)" >> ~/.bashrc
If you want it to be active immediately, then source the bashrc,
If you have a smartcard plugged in, then you should be able to see it via the GPG agent