Three Americans — Neve Campbell, Kristen Johnston and Michael McKean — and Irishman Cillian Murphy are taking to the West End in the new play “Love Song.”John Kolvenbach’s play, about a loner whose attitude is turned around by a burglary and a mysterious new girlfriend, begins previews Nov. 25 for a Dec. 4 opening at the New Ambassadors Theater in London. John Crowley (“The Pillowman”) directs. Murphy plays the story’s central oddball, with Johnston and McKean portraying his worried sister and brother-in-law. Campbell plays the girlfriend. Scott Pask, who will design the set, has worked with Crowley in the past on “The Pillowman” and on another Kolvenbach play, “On an Average Day.” “Love Song” is skedded to run through March 3.