The climax of the event will see Grade take the stage with C4's chief executive, Andy Duncan, and Five's Jane Lighting.
Thinkbox chief executive Tess Alps said it was a "combination that you won't get anywhere else" and she hoped the star line-up, along with the unveiling of some major research, would make the event a success.
Newsreader Kirsty Young has been signed up to host the event, dubbed The 3rd Age of Television, on 27 February, which will begin with the unveiling of results from Thinkbox's ethnographic research study into how viewers behave while watching ads.
It will also include panel discussion hosted by Bob Wootton, director of media and advertising at the Incorporated Society of British Advertisers, and featuring senior trading staff at media agencies.
Delegates will be able to submit their questions to Grade and co by visiting a Big Brother-style Thinkbox TV diary room, or by logging onto the Thinkbox Experience website on www.thinkbox.tv.