Brad Pitt is a fan of British band Muse. The rockers, whose sound scores Pitt’s new film “World War Z,” played a free concert Sunday at the Horse Guard Parade in London after a screening in Leicester Square for an audience including Angelina Jolie, Alice Eve and Natasha Bedingfield. We’re told Muse frontman Matt Bellamy confessed he was reading the book the flick is based on while writing their new album “The 2nd Law” and feels it was a “perfect fit.” Insiders tell us Pitt “fully concurred that this musical meeting of the minds was meant to be.” Jessica Chastain and her boyfriend Gian Luca Passi de Preposulo were also spotted at the concert.