He said it was a significant day for him and thanked the party.
"The way Narendra Modi ji and Amit Shah ji have been taking the country forward and the way the perspective of the world towards India has changed in the past two years is remarkable. I am elated to have taken this decision," Roy told mediapersons.
The actor said that he wants to contribute towards development of the country and is ready to take up any task entrusted to him by the party.
Roy made his Bollywood debut at the age of 22 in the 1990 blockbuster 'Aashiqui'. He acted in movies like 'Junoon' and 'Phir Teri Kahani Yaad Aayee'.
The actor also won the first season of TV reality show 'Bigg Boss'.