Liberty Media (L) - Get Report said Monday it will be acquiring a block of News Corporation's (NWS) - Get Report voting stock ahead of schedule.

The announcement comes a month and a half after

Liberty surprised investors -- and News Corp. chief Rupert Murdoch -- with a deal enabling Liberty to nearly double its voting stake in the media and entertainment conglomerate.

Though Liberty, controlled by cable mogul John Malone, has been a friendly shareholder in News Corp. and insisted it would remain so, the November announcement had so worried Murdoch that News Corp. ended up instituting a "poison pill" plan to thwart unwanted takeovers.

Liberty said Monday it would acquire 92 million shares of News Corp.'s Class B stock in a transaction with Merrill Lynch expected to close by mid-January. When Liberty originally announced its deal to gain control of the voting shares, Malone's media company had said it expected to terminate the transaction -- presumably by acquiring the voting stock -- in April.

In return for the Class B stock, Liberty will give Merrill 86.9 million shares of nonvoting News Corp.

Class A stock.

Liberty CEO Dob Bennett

said in November that Liberty was increasing its voting stake in News Corp. from about 9% to 17% not because of any unfriendly intentions toward News Corp.'s management, but because Liberty had seen an opportunity to buy voting shares cheaply, and pay for them with nonvoting stock the company expected to increase in value.

On Monday, News Corp.'s Class A stock fell 16 cents to $18.21, while Class B stock rose 11 cents to $18.94. Liberty's shares fell 12 cents to $10.68.