Kelli O'Hara is an American actress and singer, who appeared on Broadway and Off-Broadway in many musicals since making her debut as a replacement in "Jekyll & Hyde" in 2000, and in many guest roles on television. Kelli O'Hara is an American actress and singer, who appeared on Broadway and Off-Broadway in many musicals since making her debut as a replacement in "Jekyll & Hyde" in 2000, and in many guest roles on television.