A source tells ET that the actress and mother of three Jennifer Garner is a regular at Body by Simone, and while she usually takes private sessions, she recently attended a group class that Simone was teaching and even chose to work out in the front row. While her estranged husband Ben Affleck had a night out with Saturday Night Live producer Lindsay Shookus on Monday, Garner woke up bright and early the following morning to work out at Body by Simone in Brentwood, California.