The 43-year-old actress/dancer took to Instagram on Wednesday to announce that she is expecting her second child with her fiancé Steve Kazee. In the video she posted, Steve, 48, sang and played the guitar while Jenna lay in a bubble bath, showing off her baby bump. "Think if I make @stevekazee serenade me every night the baby will get his voice??" the Step Up star captioned the sweet clip. Jenna and Steve, an actor/singer, already share a three-year-old son, Callum. The actress also has a 10-year-old daughter, Everly, with her ex-husband Channing Tatum.