We report a rare congenital heart disease in the form of isolated fetal left ventricular diverticulum in a spontaneous twin pregnancy, detected at 30 weeks of gestation. The diagnosis was confirmed postnatally with Echocardiography and Cardiac MRI. The case highlights the relevance of antenatal screening in detecting  cardiac anomalies as early as possible to allow early postnatal work up and intervention if needed. The patient is currently 6 years old, and is followed regularly and is completely asymptomatic with no intervention required