The move was the latest development in a long-running ownership battle, as Icahn seeks to forestall a bid by the studio -- of which he already owns about a 19 percent stake -- to acquire storied rival Metro-Goldwyn-Mayer.
Time Warner Inc (TWX.N), Lions Gate Entertainment Corp (LGF.N) and billionaire Len Blavatnik's Access Industries put up rival bids of $1.2 billion to $1.5 billion for MGM, sources familiar with the matter, told Reuters on Monday.
Lions Gate's board advised shareholders reject Icahn's offer to purchase the common shares of Lions Gate he does not already own for $6 per share.
"We believe that nothing has changed -- the offer remains financially inadequate and still does not reflect the full value of Lionsgate shares," Lions Gate Co-Chairman and Chief Executive Officer Jon Feltheimer said.
The board has set a meeting for May 4 for shareholders to discuss its proposal for a defensive rights plan, or poison pill, to ward off attempts to accumulate shares.
Lions Gate shares gained 3 cents to $5.85 in early New York Stock Exchange trading.
(Reporting by Franklin Paul, editing by Maureen Bavdek)