Bruce Willis and Demi Moore's daughter Rumer, 34, joyously showed off her blossoming baby bump this Wednesday.The showbiz legacy posted a black and white Insta Stories snap that also included her little sister Tallulah, 28, beaming beside her.While Rumer stood in profile to throw her growing belly into relief, Tallulah dropped to a squat and playfully stuck out her tongue. Baby joy: Bruce Willis and Demi Moore's daughter Rumer, 34, joyously showed off her blossoming baby bump in a picture with her little sister Tallulah, 28The snap was accompanied by a lengthy caption plugging the Shaklee Meology Prenatal vitamin packs and supplements.Rumer is expecting a baby with her boyfriend Derek Richard Thomas, whom she had been dating for months before they went Instagram official in November.