Orlando Bloom is mourning his beloved dog Mighty, after sharing he believes the pup has died after going missing a week ago.The Pirates of the Caribbean star and his pregnant fiancee Katy Perry have been putting up posters and knocking on doors all week in a desperate attempt to locate the pet.Taking to Instagram on Tuesday night, Orlando told fans he's accepted Mighty has died, after he found his dog’s collar.“Mighty’s on the other side now.