Kaley Cuoco's little sister's workout body is straight-up insane. The 31-year-old actress, set to feature alongside her "Big Bang Theory" alum sister Kaley in upcoming HBO Max series "The Flight Attendant," updated her Instagram this week with a power sweat session – and she wasn't messing around. Briana, who runs her Cult LA athleisurewear line, is a known workout queen, with her training coming from her current NYC location. Together with 34-year-old Kaley, Briana is in the Big Apple for a two-month shooting stint. Check out the video below.