It is usually worn with one of the doublets and with a collar-less shirt (obtainable from suppliers to the legal profession who still wear them - in the UK at least). With a Montrose doublet, buttoned high to the neck it can be worn without a shirt, fastened directly around the neck. It was not, traditionally, worn with a PC although our esteemed "Shur Shawn" Connery has affected such an appearance and others may now copy him.