New Delhi: Bollywood actor Emraan Hashmi, who recently released a book on his son's battle with cancer, recently received a special letter for his son. The 37-year-old actor took to his Twitter handle and shared a snap of a letter that was written to his son by superstar Amitabh Bachchan. Along with the letter he wrote, "Thanks @SrBachchan for the note. Ayaan aspires to be Batman. And Batman aspires to be you. U r d original superhero!" Later, Big B took to his Twitter handle and wrote, "@emraanhashmi @Thekkapoor Really what a remarkable son .. god bless him and may he remain healthy ever ..." On the work front, Emraan will be next seen in Tony D'Souza's directorial 'Azhar.'