North Korea has started making its first documentary about Kim Jong Il's life amid renewed speculation about the 67-year-old leader's health and who will inherit leadership of the communist dynasty. The retrospective film would be a rare acknowledgment that Kim is getting on in years. South Korean newspaper Chosun Ilbo noted on Thursday that the regime began producing a similar 20-part film about Kim's late father, national founder Kim Il Sung, in 1993 - a year before he died of heart failure. The younger Kim is the subject of an intense personality cult inherited from his father. Talk of his health is considered a taboo in the totalitarian nation, and North Korean officials have strongly denied reports that the leader suffered a stroke. Analyst Koh Yu-hwan of Seoul's Dongguk University said the move appears to be aimed at laying the groundwork for naming one of Kim's sons as his successor. "A Kim Jong Il biopic would be closely related to Kim Il Sung," the professor said. "That could be used to demonstrate the inevitability of a son (of Kim Jong Il) taking over so as to make North Korean people to accept the succession as a matter of tradition." Since early this year, it has been widely reported that Kim's third and youngest son, 26-year-old Kim Jong Un, is being groomed as the heir, but the regime has made no announcement to the outside world. Pyongyang's state media said Wednesday that the country has produced the first part of a Kim Jong Il film that "will comprehensively deal with the immortal 'songun' (military first) revolutionary exploits performed by" Kim. The first part is about Kim's birth and youth, and how he advanced "military ideas and theories and tactics of President Kim Il Sung," the official Korean Central News Agency said. It is the first time the North has produced such a film about Kim, though the regime has made a number of documentaries about his public activities, Seoul's Unification Ministry spokeswoman Lee Jong-joo told reporters Thursday. But she declined to comment on what the new film might signify about Kim's health. Since 1994, Kim has ruled the impoverished communist nation of 24 million with absolute authority, leading to concerns his death could trigger chaos or a power struggle if he dies without naming a successor. A South Korean TV report recently said Kim - believed to have suffered a stroke last August - also has "life-threatening" pancreatic cancer and won't last more than five years. However, some analysts questioned the YTN report, saying Kim's brisk pace of public appearances this year make it unlikely he has cancer. North Korean state media released new images Tuesday of Kim touring a tile factory in which he appears thin but no worse off than in other recent photographs. The latest factory visit brings the total number of such trips this year to 82, compared with 57 visits during the same period last year, according to the Unification Ministry. State TV on Wednesday also aired an hourlong documentary about Kim's February activities. Kim, known to be reclusive, rarely appears live on television. However, he made a televised appearance last week in which he looked markedly thinner, his hair noticeably thinning. He also limped slightly, and his smile appeared lopsided - possibly a side effect of a stroke. The images touched off speculation that Kim, suspected of suffering from chronic diabetes and heart problems, could have other health worries as well.