The actors, who play couple Jacob and Cara Dutton in the 'Yellowstone' prequel series, tell PEOPLE how they spend their time when the cameras aren't rolling

Helen Mirren and Harrison Ford grew thick as thieves on the '1923' set, with Mirren calling Ford a 'bloke' that she loves to 'hang around on set' with, and Ford calling Mirren a 'real cool lady.'

We had really good rapport, and I was lucky because almost 80% of my time is with him, and so he makes me laugh,” Geraghty tells PEOPLE