In a deal that hearkens back to the “golden age” of radio and the early days of television, the giant Omnicom Group of advertising agencies may partner with NBC to produce a musical special starring Jennifer Lopez and line up sponsors for the program from its client list, the Wall Street Journal reported Thursday. The newspaper observed that although such an arrangement would free the network from having to secure advertisers for a costly production during the current downturn in ad spending, it would also reduce the number of spots NBC would be able to sell during the special. While both NBC and Omnicom confirmed the talks, each noted that the deal has not been completed, the WSJ said. In the early days of television, advertising agencies (some of which have since been absorbed by Omnicom) commonly produced programs “in-house” and often attached their clients’ names to the titles (Colgate Comedy Hour, Lux Video Theater, Philco Playhouse, etc.).