Kaley Cuoco's baby bump made a cameo while the expecting mother filmed for her upcoming series Based On A True Story.The 37-year-old actress showed off her growing baby bump in three casual and comfortable outfits while on set in Los Angeles on Thursday.The Big Bang Theory alum - who revealed last year that she is expecting her first child with boyfriend Tom Pelphrey - donned an all-black outfit as she arrived and stepped out of her car.She wore a simple, black long-sleeved top paired with black sweatpants.The California native tied her brunette tresses up in a messy bun and shielded her eyes with a pair of retro vintage round sunglasses.