In 2008 we showed by Monte Carlo simulations of the long-term dynamical evolution of the Oort Cloud that the current comet injection rate estimated from a complete model including both Galactic tides and passing stars by far exceeds the sum of the predictions from models using only tides or stars. We have since then investigated in detail the origin of this synergy, and the results of this work will be summarized and explained. The long-term synergy caused by filling of the Tidally Active Zone will first be reviewed, and then we turn to the 'real-time' synergy occurring due to the combined tidal and star induced dynamics during the last revolution of injected comets. We pay particular attention to the likelihood of identifying the main culprit stars using astrometric surveys (Hipparcos and Gaia), showing that the latter holds promise for revealing the origin of observed new comets.