Megastar Amitabh Bachchan, on his 70th birthday Thursday, was at the B-Seventy art show which was inaugurated by Kokilabein Ambani at Nehru Centre in the evening.B-Seventy, a unique art show, showcase the art works of 70 of India's leading artists. All these work have one thing in common - their inspiration as each of the works is a tribute to the megastar on his 70th birthday.The entire Bachchan family was present at the event.B70 covers a varied gamut of genres of Indian art. These include modern and contemporary art, sculptures, photography, mixed media and even an installation.