Senior Congress leader and former Union minister Kotla Suryaprakash Reddy and his family members on Saturday joined Andhra Pradesh's ruling Telugu Desam Party (TDP). Suryaprakash Reddy, son of former Andhra Pradesh Chief Minister Kotla Vijayabhaskar Reddy, his wife Kotla Sujatamma and their son Kotla Raghavendra Reddy joined the TDP in the presence of Chief Minister and TDP President N Chandrababu Naidu.