Patti LuPone returns to The Late Show for a fascinating conversation that centers around her friend and mentor, the late Stephen Sondheim, who she lovingly describes as a \u201ctaskmaster\u201d in rehearsals.\nWe want your feedback on The Late Show Pod Show with Stephen Colbert! Visit\xa0http://www.colbertlateshow.com/podsurvey\xa0to take a brief survey.\nLearn more about your ad choices. Visit megaphone.fm/adchoices