Rupert Murdoch promoted his eldest son Lachlan Thursday to a more prominent role in the family business, media giant News Corp. ( NWS).The company said that Lachlan Murdoch, who now runs News Corp.'s Australian operations and its U.S. print holdings, will add the title of deputy chief operating officer to his portfolio. Lachlan Murdoch, 29, will report to Peter Chernin, the media conglomerate's president and COO; Rupert Murdoch has dubbed Chernin his immediate successor, though Lachlan has long been regarded as the family's chosen candidate to replace his father. "Lachlan has demonstrated enormous skill and agility managing a vast array of assets on two continents, and his promotion ... is a reflection of his great success running our Australian business and U.S. print operations," Chernin said in a statement. Lachlan is credited by the company for improving profits in the Australian group, for record profits at book publishing unit HarperCollins, and for improving circulation at the New York Post. Murdoch's other son, James, 27, was promoted to executive vice president of the company a year ago -- almost exactly to the day -- after a stint running News Corp.'s digital operations; James, too, reports to Chernin, and he runs News Corp.'s Asian satellite unit, Star TV. Rupert Murdoch said last summer that all his children had to "prove themselves first" before a longer-term succession plan is solidified. News Corp.'s ADRs fell $3.81 in Thursday trading, closing at $48.81.