It was leaked weeks ago but the players involved in the new premium network wouldn’t confirm officially: Mark Greenberg is president and CEO of the new premium entertainment JV recently announced by Viacom (NYSE: VIA) with MGM, Lionsgate and its own Paramount Pictures. Greenberg had a long career at Showtime, including leading the sports and programming, launching Showtime On-Demand, sales and affiliate marketing. When he left he was EVP responsible for corporate strategy, new biz dev, digital media and more. This may have started as Viacom CEO Phillipe Dauman’s idea but it’s going to be up to Greenberg to make the Showtime-HBO-Starz competitor work.

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The announcement about Greenberg stressed again that it is to launch in fall 2009. A few little details to take care of first, though, like distribution. Comcast (NSDQ: CMCSA) CEO Brian Roberts didn’t leap at the chance to sign a sheet when Dauman joked about having one ready for signing during at a joint appearance Sunday at The Cable Show in New Orleans. Release